Thanks for the feedback 
In my eyes, politically, cultures that are expansionist or greedy would probably suffer a small hit in diplomacy. If you're trying to rapidly expand your borders, it's probably going to generate friction with other races. Likewise, if you're greedy, the general self-serving material greed coming from your population would probably cause some friction with other races. I think the best analogue to that would be the Ferengi from Star Trek. If you've got any suggestions on what penalties might better suit these traits, I'm definitely open to ideas.
Opportunistic? My thoughts there were that a race that is known to quickly jump on advantageous situations (in my experience with AIs that use this setting, it really just means they declare war on you if they know they can easily win) would be treated with some degree of distrust by other races, thus the diplo penalty. I can see this one as debatable though, but I'm basing it off of how the AI plays with the opportunistic personality (like a scumbag).
I don't really see any of these negative diplo modifiers as too harsh, though--it's so easy to build up a good diplomacy score through the tech tree, or though building embassies on your planets.
In regards to expansionist, thinking it over a bit more, yeah, I think the -1 to morale might be a bit nasty early game, as you say, they'll have the large empire penalty to deal with later on. I'll take that out and replace it with something more fitting when I create the next version.
Admittedly, yes, a lot of the penalties I feel could be a bit better. Going through the list again, the main ones I'm not perfectly content with are:
-Cultural
+10% influence
+1 morale
-10% soldiering (From the thought "hey these people are nice and want to spread their ways and don't want to kill people", but then maybe their culture is centered on killing people...)
-Expansionist
+10% influence
+10% social production
+10% growth
-1 diplomacy
-1 morale (Like I said above, not too friendly early-game with the large empire penalty)
-Trader
+10% wealth
+15% trade route income
-10% research (From the idea "hey they're spending all their time trading and building and not researching", but tech can be something very profitable too. Open to suggestions here)
-Greedy
+15% wealth
+5% trade
+10% tourism
-1 diplomacy
-5% research (I'm still okay with the diplo penalty, but the -5%s on research and production I feel could have something better. I'm open to suggestions.)
-5% military
-Spiritual
+1 morale
+10% growth
-5% social (Again, I don't think the small production nerfs really fits too well. Maybe a reduction in trade and tourism, from the idea that they wouldn't want to trade heavily with opposing ideologies, and opposing ideologies wouldn't want to visit because of that underlying hostility?)
-5% military
Still though, I definitely want to keep penalties on these. Despite the nature of the mod, a huge line of free bonuses is sort of cheap gameplay-wise, and I feel that the personality of a civilization should both have positives and downsides. It might take a bit longer to get everything fleshed out with both positives and negatives, but that's fine by me
I'd seriously love to get everyone else's feedback though. If you don't want to download the mod to see the stats on these, here's the list:
-Aggressive
+10% military production
+15% social production
-5% influence
-1 diplomacy
-Xenophobic
+25% social production
+25% resistance
-20% range
-10% influence
-1 diplomacy
-Cruel
+5% hitpoints
+20% soldiering
-1 diplomacy
-10% growth
-Cultural
+10% influence
+1 morale
-10% soldiering
-Opportunistic
+10% wealth
+10% military
-1 diplomacy
-Expansionist
+10% influence
+10% social production
+10% growth
-1 diplomacy
-1 morale
-Trader
+10% wealth
+15% trade route income
-10% research
-Greedy
+15% wealth
+5% trade
+10% tourism
-1 diplomacy
-5% research
-5% military
-Spiritual
+1 morale
+10% growth
-5% social
-5% military
-Diplomatic
+2 diplomacy
+10% influence
-10% military
-5% social
-Scientific
+20% research
-5% social
-5% military
-Peaceful
+1 diplomacy
+1 morale
+10% social
-10% hp
-10% soldiering
