So I'm trying this game out for the free weekend, I want to like it (SMAC was amazing) but.....
The AI is actually, somehow, WORSE then civ 5 - ARC declared war on me, suicided a few units into my city (did about 10% damage) then moved the survivors away.... only to move them back a few turns later, but they got killed before they could even attack. After that she just sent units in one at a time to their death, and every dozen turns or so she demanded I give her one of my cities in exchange for peace. Then some other AI declared war on me and move all his units into the water near my city where they could easily be killed in one hit
Civ5 AI was terrible, but at least it pretended to try.
The AI also does the same cheating ICS crap it did in Civ5. The player is strongly limited in his expansion by health (I found it nearly impossible to manage with only 3 cities) but the AI has no problem filling every corner of the map with garbage cities because (presumably) it gets huge cheat bonuses.
Espionage seems overpowered ~1000 power every 20 turns, or ~+50 power/turn PER AGENT, 100% free? I never built any generators and ran a massive power deficit the whole time because I could just siphon infinite power from the AI (probably because he has huge cheat bonuses to his power income....)
Tech web is a mess, just a huge mess. I ended up picking stuff more or less at random because it was difficult to get a good idea of what led to what, and which techs were important. I guess you would eventually get used to it, but... it's just a mess.
Navy ships seem overpowered, send 3 - 4 of them in and just completely blow up a city in a single turn, send in a single melee unit and mop it up. No setup time + huge damage + very tough, and not really very expensive to build? Building coastal cities is suicide.
Graphics are terrible, I hate to complain about this because I don't really care that much about graphics but... everything is just a blurry mess that runs together (I had it set on high). it's hard sometimes to tell which tiles have miasma, especially forests... because it all just blends together. Civ 5's graphics were decent enough and very readable, why did they ruin them?
Overall... not only does it feel like an expansion pack, it feels like a rushed, poorly done expansion pack. I can't believe I'm actually typing this, but I actually feel more let down by this then I did by Civ5 vanilla.
Edit forgot to mention the trade routes, which are very annoying to manage, and for some reason seem to die every 20 turns or so, so that you have to click through and start them up again. Why can't they just be automatic?