Religions - Apart from the +2
shift for adopting a religion present in a city there isn't much benefit to it. I personally don't think adopting a religion is worth the faction hit I'll take against civs with opposing religions.
That's the way Civ4s diplomacy always worked, you can't be friend with everyone. Indeed, it's questionable if you should adopt a religion as state one, if you are the only faction, but things change if there is another faction following it. You get one friend for several enemies, but it better then to be neutral with everyone (diplomatic actions like tech trading, bribing into wars or DPs require good relations). See also my idea for shrines below.
In addition, I find it very unsettling that you don't get a free disciple when discovering a tech for a religion, just for founding it. If you don't found any religion at all you don't have any control over. I'm sure this was intentional but is there a reason why? Some of them are quite powerful just to have in your city.
I'm rather used to BtS, so it is normal for me...sometimes other factions will actively spread their religion in your faction, maybe that should happen more often. I'm undecided about if a disciple for everyone reaching a certain tech would
improve things...it may level the playfield, but takes away another incentive to found a religoin
Planet Attitude This is maybe something else I don't understand very well. There seems to be a tipping point. Specifically if you can stay in the green PA the planet seems to like you. Fungal blooms rarely happen and if they do it's on the border of a neighbor. The native life seems to go after the other civ instead. Therefore fungi in and near your borders is safe for you. This ups your planet attitude some more and endangers your neighbors. It also happens to bring culture as well. If you can stay in the positive numbers of planet attitude you also get a power/culture boost. Even 1
/turn is more than enough to win an expansion war ... which can net you more fungal lands and more planet attitude etc ... Nevermind that positive PA will let you have native pets as well, perfect for dealing with the more tech advanced civ armies. I haven't seen the AI able to counter this strategy at all. All too often I see other civs surrounded by fungus with badly negative planet attitudes.
Yes the AI needs to get better at it and it also needs to learn how to run the opposite strategy. Still most Civs switch to Hybrid after leaving EB (which further weakes a terraform startegy, as you get isolated). In my games, it's not always the way that Deidre is up and Miriam down. Miriam runs usually one of the biggest factions and tends to farm her entire land...
Maybe it is the emperor difficulty I'm playing, where the AI gets more boni - this might give them more means to cope with the dangers of native life. You can be sucessful as terraformer as well, but the Way of the Planet is still easier for my taste.
I'm pretty sure that we will see more improvements here in the future, as Maniac mentioned this as one next step in the poll thread, if a better AI will be the focus (and the vote goes in that direction currently)
Voice of the Planet - This brings me to this puppy. It seems to be the most powerful religion hands down. Not only is it the first available it's disciples are cheap but the White Pines is incredibly good. If you own it you are basically getting 2PA per new city (4 if you are Dierdra). When I first started playing I always went for this and I crushed. Looking for a challenge I upped the difficulty and Dierdra was always my primary contender (although occasionally she had a bad start and the University dude was score leader.) I'm sure there are counters to the VotP rush that someone can point out. Although it is one of the holy shrines to build, its far superior to the others. I suggest halving the PA bonus for the shrine.
Hmm, maybe you should get the shrine bonus only if you adopt a religion as state one (or it should be cut by 1/2 without at least)? That would give another incentive to set up a state religion.
If it's only VoP which is too strong a simple reduction in PV gain might be enough. I haven't settled my mind here...as said above it is hard to evaluate a Terraformer strategy if you pay for it all the time with being an outlaw...
Civ Flavour - I find the differences between the civs is very minor. Except for their diplomatic preferences there isn't much real difference. Any plans to add unique units or buildings or add traits?
I think the reason is just that the original SMAC did not offer more variances as well and that the factional boni get converted into "headquarter buildings" partly for Planetfall, as Orlanth explained. UUs and real UBs would be great additions, I agree - but first we would need to have ideas, for BtS civs the source is just human history, here it's brainstorming in science fiction world.
Civ Leaders - I noticed in the Datalinks there were a lot of other civ leaders but they don't seem to be active. It makes it somewhat troublesome to play with more than seven civs at a time. It's a pain to figure out exactly which Yang is demanding I convert to Police State all the time. Any plan to add them in? Or any of the SMAX factions? If you'd like I could suggestion some separate civ/leader changes.
Thats probably the most frequent request in the last feew weeks
Maniac said that they will come in future (Cha Dawn and Aki Zeta as 2nd leaders of Gaians/University, the others as new factions, some entering the game later), but not too soon.
Scientists and Hackers - I'm a bit puzzled at the lack of Scientist GP. In fact, you won't be seeing any of them at all until late game unless you get the Human Genome Project. This flies in the face of what I see as the obvious GP choice in Planetfall. Do you try to get an early great scientist for an Academy and increased general science output or do you try for another one to lightbulb a tech or build a holy shrine? Most civs however get an early great hacker, which I
don't think can lightbulb anything early game, so it gets burnt for a wonder. This ensures they get another great hacker next time around. I like that you have a variety available early, but all I really see out there are hackers. In addition, I find it very annoying that I have to take all my cities off of auto management. As soon as they pop it always seems to be a new hacker instead of a workable plot or even a genejacked citizen. I haven't played for long but on more than a few
occaisions I got a great hacker instead of the GP I was trying for because the pool got diluted by my lack of micromanaging.
Lightbulbing techs for Hackers is planned to be added, IIRC. Eventually some civics will open slots in future as well. There was already a change to how the governor weights hackers vs. other specialists, but that only works if there are better slots available. Late Scientists, Merchants and Engineers are more powerful, so it is intended that there aren't many early slots.
With all these great hackers is there anything new up with Espionage in Planetfall?
No new missions, but some of the old have gotten more important. Tech stealing (because you trade as much), treasury stealing (credits are often scarce) and creating unhappyness/unhealthiness (might overthrow bases into native revolts, if the population starves) come to my mind. No SMAC style mind control and no SMAX freeing of defeated leaders, though.
Too much FfH I suppose. But even with the differences in scope between the two mods, I do find Planetfall somewhat lacking in this department.
rate (attracts intellectual elite)
), I will rack my brains for some interesting new effects!
for 
from the university without them actually loosing any (will be hard to balance I guess). Thus creating a dependency to this warwise weak civ. University should never start a war... almost.
per 2 non-Citizen specialists (mistrust of elitism)
in squares with 4
trade would have to be coded, either by modding 
