If you love CIV IV, you will most likely hate CIV 5, here's why:
Absurdly Lacking MP Support
No improvements at all from CIV IV: No dedicated servers, no matchmaking, constant lag issue, framerate problems, no online ladder and rankings, no unit animation, random crashes, no way of reconnecting a game, no way of joining a mid-game through invite.
I only played Civ IV through LAN, and we just saved and loaded if we had to split a game across sessions. I do find the lack of MP matchmaking disappointing though.
No SP Scenario
SP consists only of "Play Now" and "Custom Game". It doesn't get any more plain than this. And it has the stench of "sloth" and "greed" all over it.
I never once played a scenario in Civ IV, Warlords or BTS so this doesn't matter to me at all. I'm sure I'm not the only one.
No Tile Animation
Why the **** is this taken out? Why must players have to go into the city menu to see what tiles are being worked on??
I agree here. I would like this to be patched in at a later date.
No Religions
Religions weren't necessary, but it added flavors to the game. It was awesome trying to spread your state religion to the whole world, earning diplomatic favors and gold in the process. CIV IV lovers want the religion system to enhance so that it can impact the game in a more meaningful way, not remove it entirely.
Religion was ok but not that great. It was pretty binary, everyone of the same religion became allies and everyone else was an enemy. It made the AI really annoying because they would compound their research bonuses at higher difficulties by trading with each other leaving you really far behind, so I didn't like it.
No Espionage
Espionage was one of the best features to have been introduced in the CIV series. It gave players so many options and alternatives to go against their opponents without the risks of declaring open war: poison their water supply, scout out enemy troop strength, stir up a rebellion, steal their treasury, sabotage their wonder construction, etc. Why is this awesome feature removed completely?
I felt this was the worst addition to the game. The things a Spy could do were only minor annoyances and I didn't care to have to fortify Spies all over my empire to try to avoid sabotage and poisonings. The AI would seemingly gang up on me with Spies and I couldn't afford the production to hit them all back equally hard.
No Civics
Civics was another extremely well-thought out feature that was added in CIV IV. Not only did it add flavors to each nation (Communism vs. Capitalism, Emancipation vs. Slavery, Universal Suffrage vs. Police State), it provides long term tactical options as well as short term flexibility to players to adapt their empires based on the current circumstance. Deciding and changing Civics was always a weighty decision because each one of them have their pros and cons. It makes each nation unique because rarely do two empires have the identical set of Civics.
In CIV 5 Civics are replaced by Social Policies, which is fundamentally a ladder of perks with bonuses that you can upgrade one at a time. It may still be strategic to decide on which branch of policies and perk to upgrade, but because of the fact that they are permanent and you cannot change them, they offer absolutely no tactical flexibility to players. All branches and perks add some kind of bonus to your empire with no negative side effects, so the decision of choosing which one to upgrade also becomes less significant.
I like this change. I didn't particularly enjoy flipping Civics all the time depending on what I was doing at the moment. I also feel that some leaders being able to flip Civics without revolution kind of defeated the purpose of having different Civics. Why not just make it an upgrade tree if you're going to have all of them available whenever you need them anyways?
No Hamlets
Hamlets was an important tile improvement in CIV IV as the primary commerce provider. But its greatest strength is that over time it evolves into a cottage, a village and ultimately a town, encouraging players to build them early to reap the benefits.
In CIV 5 hamlet is replaced by "trading post" which has a MUCH uglier model and does not evolve.
I somewhat agree. I like the idea of an improvement that gets better the longer it survives without being pillaged. However, later in the game it was a huge pain to defend all your cottages and it just wasn't possible to prevent pillaging. After each war, I'd have to start a ton of cottages from scratch. Since Civ 5 has 1UPT, pillaging would occur even more with invading armies not sticking to 1-2 large stacks. If we still used Hamlets->Cottages, the aftermath of a war would always leave you horribly behind everyone economically with little hope of recovery.
No World Wonder Movies
Now all we get is a still picture and some quotes that most people don't give a **** about.
Wonder movies were nice but honestly it's a waste of resources from a budgetary standpoint. They're kinda nice the first time but I always skipped them anyways.
No Commerce, Research and Culture Sliders
Commerce, Research and Culture used to be interlinked in building your empire. Any of these resources can be distributed freely using sliders to let players develop their nations in the exact way they want.
In CIV 5, commerce, research and culture are completely separate entities. And the only decision players can make is to decide how much of each resource to produce.
I'm fine with this. It just means that research won't ever slow to a crawl because you had to make some units to defend or prepare to attack. Since tech trading doesn't exist anymore, you can't demand tons of techs to catch up in research from the civ you are dominating, so war would be far too punishing on your research level if it stayed tied to your commerce.
No Random Events
Random events provide small bonuses and surprises to your nation in the way of additional income, one additional food resource, increased culture, etc. Those bonuses are no way game-breaking, but they make you smile every now and then and make your empire feel like a real nation inhabited by living breathing people rather than some numbers and data on the screen.
City-states giving you quests is basically like the random quest events in BTS. As for other random events like +1food or stuff, I guess natural wonders replaced that.
User Interface
Firaxis might have thought that they were very clever in making the UI much more streamlined and linear, but it is NOT! This type of UI may have been ideal for the console version of Civ because of the limitation of the controller, but for a PC CIV this kind of UI brings more inconvenience and frustrations than otherwise.
PC gamers want data and information easily accessible, laid out clearly right in front of them, instead of clicking through menus and menus before finding out what they want to know.
I don't find the interface to be very console-like and it seems to work fine. I'm kind of glad the interface doesn't look like a spreadsheet anymore, when I play Civ I want to play a game, not an Excel spreadsheet.
City States
I really question the point of implementing City States. It may be fun to interact with them and build a good diplomatic relationship with them, but more often than not it's much easier, simpler and faster to just conquer them and take their resources than to waste gold buying their friendship.
The importance of City States as allies in war times is extremely limited too, considering that now military units cannot stack, and City States have such a small territory, their army size and strength naturally become very restricted.
I think they're a nice addition to the game. They fill some of the empty space and give you some nice bonuses if you Ally with them. In fact, those bonuses may be essential to winning Cultural victories because having more cities increases social policy cost, but having cultural city-state allies gives you massive bonus culture without the penalty of having more cities.
Framerate Problems
Even on Medium settings, and according to the requirements of the game my PC is more than enough to handle this game on High. It's painfully obvious that this game wasn't optimized.
I'm at the roughly the Recommended spec level (3GHz dualcore, 4GB ram, HD4870 512MB gpu, Vista x64 SP2) and I have no framerate problems.
No Leader Personality Traits
It provides a historical and semi-realistic flavors to each leader. And although some traits provokes controversies and debates amongst historians for their accuracy, it's part of the fun too.
The traits were kind of nice, but they ended up having to make too many to give each leader a unique combination and some of the trait abilities were clearly much better than others.
One Leader Per Nation
Is it really that much to ask for to have at least two leaders, even for a Vanilla pack?
It's easier to think of a nation when symbolized by a single leader figure. I don't mind it.
Conclusion: If you are a CIV IV fan, you will most likely hate this atrocity of a "sequel". Sequel, by definition, is supposed to improve on the original by fixing predecessor's flaws and enhance its strengths. But ironically CIV 5 has actually completely removed some of the strengths that made CIV IV so enjoyable, instead of building upon them and perfecting them.
CIV 5 is infested with extremely questionable designer flaws: Lack of tile animation, no World Wonder movies, the streamlined linear UI, just to name a few.
The extremely lacking single player and multiplayer aspect of the game is just utterly unforgivable, emitting the overwhelming impression that the entire package feels very incomplete, and you wonder if Firaxis did this intentionally knowing that the committed mod community will do their job for them.
I loved Civ IV. I played hundreds of hours single player and maybe a hundred hours LAN. My personal preference was Vanilla or Warlords (just for the Warlord GP) because I didn't like Espionage in BTS. I think I didn't like BTS because many of it's changes affected Modern Era, and I hated combat so much that I never liked Modern Era. I really, really hated having to produce dozens of units at a time to make massive stacks to either attack or defend. Combat stopped being fun for me after it started to require more than a dozen units.
I enjoy Civ V more than I did Civ IV, mostly because combat doesn't require managing hundreds of units anymore, and I won't be going back.