Aircraft: Doc: Airpower in SMACX was a pivotal beeline, as it was very overpowered. Once researched you could park your aircraft over your advancing columns and then attack with impunity, as the AI either didn't have Doc: AP yet, or else typically didn't do a good job of building interceptors or anti-aircraft units to deal with this strategy. I do think BE does a better job of limiting the effectiveness of aircraft by making them into more of a long range artillery unit.
Spies: nothing was more annoying than having the SMACX AIs walk their spies up to my city doorstep and then run out of movement points where they were then easily picked off on my next turn. And infiltrating AIs with your spies was so overpowered , as you could then see everything the AI was doing from that point on in the game. IMO spies in BE are better as they are more limited in their capabilities and benefits (such as only being able to "see" what is going on in the city the spy resides in), and once a spy is killed the benefits it was providing (specifically the city view it was providing) goes away.
Aliens (native life forms): after the early game in BE the native life dwindle and become inconsequential, which is by design, whereas in SMACX they are an incremental part of the game up until the end. From a "a game should be an interesting series of choices" perspective, I think SMACX is better as the aliens continually engage you throughout the game, and it is something you as a player continually need to take into account.
Easter Eggs: in SMACX you have the two hidden factions (Sid and Brian) as well as the Skybase icon, to name a few Easter Eggs. I don't see any in BE.
Unit variety: SMACX had a plethora of units, including infantry, speeders, hovertanks, submarines, aircraft carriers, jets, copters, missiles, nukes, and satellites.
Subs, copters, missiles are all missing from BE.
Theme: from the GUI, to the Facility quotes (such as for the Research hospital), to the Secret Project videos (such as the Dream Twister quote about the last transmission from the Spartan base Assassin's Redoubt), SMACX continually reinforced a dark theme. Deadlock had a campy, don't take us too seriously theme running thru it. I don't know if there is a theme per se for BE.
Graphics: SMACX in-game graphics (specifically the terrain) were awful. I remember looking at the box the game came in and not seeing a single picture of the ingame screens on it - the devs knew it was "not a selling point" for the game. In comparison BE's environments are top notch.
For Wonder Movies/ Secret Project movies, SMACX's Secret Project movies blow everything out of the water in comparison: they tell a story relevant to the SP which was just built, and was always a drawing point for me to play "one more turn" so I could see that next Secret Project movie. I don't even look at the screens that pop up in BE as they aren't engaging to me in the least (and I don't build a lot of Wonders in BE, as they just aren't that wonderful).
And then there are the intangibles such as the SMACX videos when capturing an enemy leader. Again, this was a "one more turn" event where I wanted to see Yang, or Miriam, or Zakharov in the Punishment Sphere.
Modability: SMACX used the pcx format for its art, which although a PIA to deal with still led to a lot of great faction and ingame artwork. And for creating new units, all I had to do was enter one line in the alpha(x).txt:
Seawolf Mk2, Cruiser, R-Bolt, 9-Res, 6, 4, 0, Metal, -1, 00100100110000000000001100000
And I created a new unit ingame. For BE it takes a graphics artist and someone editing how many files to create just one unit?
Writing: here are some examples from SMACX:
Not only does God play dice, but the dice are loaded!
Richard Baxton piloted his Recon Rover into a fungal vortex and held off four waves of mind worms, saving an entire colony. We immediately purchased his identity manifests and repackaged him into the Recon Rover Rick character with a multi-tiered media campaign: televids, touchbooks, holos, psi-tours-- the works. People need heroes. They don't need to know how he died clawing his eyes out, screaming for mercy. The real story would just hurt sales, and dampen the spirits of our customers.
The Academician's private residences shall remain off-limits to the Genetic Inspectors. We possess no retroviral capability, we are not researching retroviral engineering, and we shall not allow this Council to violate faction privileges in the name of this ridiculous witch hunt!"
What goes up, better doggone well stay up!
A handsome young cyborg named Ace, wooed women at every base, but once ladies glanced at his special enhancement, they vanished with nary a trace.
These are just a few of the gems from SMACX. There is nothing that can compare in BE to the level of artistry that SMACX writing presented.
Random events: SMACX had Stock Market crashes, Promethean Virus outbreaks, network crashes, volcanoes, meteor impacts, etc. These were a real PIA to deal with, and in PBEM were banned because they were unbalancing. I think BE is a step in the right direction by doing away with random events: while they did add to gameplay, they weren't part of the core game experience, and were typically more of a nuisance than an enhancement to the game.
Orbital layer/ warfare: SMACX version of orbital warfare came towards the endgame, and was in a completely separate screen, and really wasn't intuitive. BE's orbital layer comes early in the game, and has a direct link to the planetary units (such as being able to shoot down satellites). BE's implementation of the orbital layer is definitely more engaging and enjoyable IMO.
Unit Workshop: I am one of those who really enjoyed building units (either in the workshop, or via adding units to the alpha(x).txt file). And I always appreciated having the ability to build unique units to suit the environment (such as empath units for fungal worlds, or nerve gas units to deal with the Progenitors).
Stations: To me Stations are more of a nuisance than anything else, as they always seem to land right where I am planning to build another outpost (or to put it slightly differently they are like a negative random event, such as earthquakes, meteor strikes, etc.).
Intangibles (such as the Holobook, the videos for capturing enemy leaders, etc.): SMACX wins this hands down, and again this is a "one more turn" event where I want to keep playing to see that enemy leader put into the punishment sphere, or finish a game so I can see the holobook quotes, etc.
Computer system requirements: SMACX can be played on any system that's been built in the last 15 years. BE needs a high end graphics card, which if the devs aren't going to have Wonder movies, then why not back off on the other graphics in BE so that the game can play on older computer systems (i.e. which would create a larger pool of potential customers for the game)?
1UPT vs MUPT: everyone has their opinions on this. Mine is simply that both are limited (if I lose a single unit in either SMACX or BE, then I probably did something stupid, as neither AI is really that good IMO), however it is a variant to the puzzle that is the game that I have to figure out.