Preface: a lot of tl;dr in this post. sorry for the rant and text wall... thank you for your understanding. - dilettante
Predictability is not necessarily a bad thing.
People in Civ5 lambast the diplomacy is quite opaque and unpredictable/unstable. (i think its been dealt with last patch)
People in Civ4 lambast shady vegas odds-makers for supplying false odds in combat situations. Supplying odds was supposed to have fixed spearman vs. tank FTW but whatever... we won't go there. (99% my butt... two losses to the same unit both vs. 99% = rage quit.)
People in Civ3 lambast the AI for trespassing/declaring on your land without hints... sneaky sneaky.
I love Civ3 but also love Civ4. What I love about Civ3 is its pick-up & play mechanics and simple yet elegant graphics, also it's uncluttered UI. It's like comfort food, predictable yet solid and delivers in the clutch.
What I love about Civ4 BTS is factional warfare, diplomacy, vassals, the Revolutions Mod, role-playing AI civs, and yes religion but only because it adds to tension to diplomacy - also trading, tech diffusion, random events, and an open source which I can change the whole ruleset if I know Python better. (I know, i know... Civ3 has an editor).
What I hate about Civ3 actually didn't come until Conquests. Marshlands and other weird things that weren't in the vanilla game (i came to civ from civ3 vanilla), it had a six button elegance and now it has so many buttons in conquest. Yes, some of my complaints are nitpicky things but they still bug me... and none of those complaints are from the base game itself... the conquest game is fun. too many new unit types IMO but they're not overbearing.
What I hate about civ4 is stat-addiction micro... Goodness, Civ4 people complain that civ3 has a lot of micro on higher difficulty levels with no overflow, etc, etc but seriously... just look at a city screenshot of 3 and a city screenshot of 4. I prefer 3's uncluttered look.
And don't get me started on how many pieces of information you need in each advisor screen. Do I seriously need to look at a damn excel spreadsheet if I'm looking through domestic advisor? Do I seriously need to look 3 damn times if my citizen allocation is correct in Civ4 cities because it keeps on shifting? Oh and let's not talk about specialist allocation, I HATE specialist economy because of stupid micro... it's a great strategy to win at high difficulty levels in 4 but designed for OCD folks.
I know civ4 is the OCD, min-max, micro-civver's greatest-game wet-dream EVAR but come on, I don't want to be at work when I'm playing, enough with the stupid excel and number crunching, I see it all day long, I don't wanna see it during civ games.
Another thing is the UI. I already mentioned the sheer amount of info. But I don't need nor want all of it. Seriously, who reads every single thing in the city screen from civ4? I don't have time to read it all. It speaks to Civ3's elegant UI that I can look at a city screen for 10 seconds max and get every single info I need.
Graphics are not a big deal to me but I like's Civ3's graphics. Civ4, as previously mentioned in another post, has a 3-d cartoony look. It is what it is but I don't see logic behind the graphic change from Firaxis, Civ3's look was fine... timeless and classic... like a TBS game should be.
The other thing I hate about Civ4 is the sheer number of unit types and the stacks it creates. The AI only knows to defend and to defend with a mountain of troops at its cities. This combined with the 99% odds fail and we got a frustrating way to capture and conquer. I know Schafer tried to break this in Civ5 and kudos to him for trying and failing, at least he tried to lessen this insanity. I've never seen a 50 defender stack in a Civ3 AI city, have you?
The number of unit types is insane. There's no predictable route and players are concentrating more on what units to bring in the stack than how to whittle the enemy to pieces. Often, a hit-n-run tactic won't work because the enemy won't chase you. And the unit-counterunit thing doesn't even work on offense, because if you try to pick the unit that will counter the defender, it will bring up the counter-unit to defend. I've tried and failed to break stack advances by sending a forward army to break the stack into pieces and it fails everytime because the counter-unit thing comes up...
all hail the pancake stack...
There are other complaints such as no era lock tech to discover and tech locks are flimsy at best, i.e. you don't need drama to have broadway. you don't need flight to have rocketry, etc. but a lot of those are minor.
Funny thing is that I love Civ4 BTS. I really do... but I have been modding the game ever since I got the complete edition to make it play like Civ3. What does that tell you?
If I were in charge of Civ5 (yeah right, I would've screw up that game so bad), I would've had the best of Civ3 and the best of Civ4.
but... that's just my two cents.