I'm kind of okay with specialists as they stand, because in my experience tile yields tend to be pretty low (with a few exceptions), so I spam farms pretty much everywhere I can and then let cities grow big. My last game ended with several exceeding 30 pop where they usually had only 20 map tiles (based on viability and shared tiles due to proximity to other cities). So even if specialist yields are low they're basically free yields because otherwise the city couldn't have done anything with them anyway (except leaving them unemployed for +1 prod). There's also already something (I forget if it's a wonder, tech, or policy) that increases all specialists yields by +2 energy.
That said, I would like to see improvement yields improved (especially the late game ones like dome, array, academy, etc). Like xenomass wells, there's two or three techs (and a wonder) that improve farms but far less that improve mines, quarries, terrascapes (1 policy only), or generators (they do a bit better but still not as good). I did like the idea floated by someone earlier where adjacent terrascapes reduce their maintenance costs but I'd wager that'd require the equivalent of .dll editing in Civ4 (which is impossible in Civ5 and thus probably impossible in BE).
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Also, just noticed two "bugs" that existed in Civ5: Puppeted cities automatically focus on commerce/energy (building only wealth producing buildings and then converting production to wealth when no more exist), but this focus remains when you annex the city (IMO it should default to unfocused). Also, the Quick Combat/Quick Movement options don't save themselves in the Advanced Start menu. This is particularly obvious since all the other options do save themselves between games; it makes no sense to me that these do not.
Obviously these aren't game breaking issues but they do feel like oversights that you'd think could be fixed in five minutes if anyone actually involved in developing the games actually played them...
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Also also, does anyone know a compiled list of quests (particularly from constructed buildings; why the hell are these things called "quests" anyway?) and their rewards? In my last game there was one that prevents aliens from attacking trade units - which was a total no-brainer compared to other option - but I forget where it came from.
Edit:
Some here and
building quests here. Ultrasonic fence is what I was thinking of.