Sounds like culture points are the only binding constraint. No exclusivity.
So, you can have Aristocracy from tradition tree AND liberal democracy=type things from the Liberty tree, and get both benefits simultaneously.
You really don't think any current Liberal democracies have Aristocratic elements to their society?... Specifically aspects of that society that would aid and encourage Wonder production.... look at Mt. Rushmore
Many societies are 'equal parts tyranny and libertarian' or perhaps not equal, but none are purely one or the other.
I don't like this. Social policies should have tradeoffs, not be More is Better.
Social Policies are now the Equivalent of Techs, but with non-entagling trees (imagine if the tech tree was 4 straight lines from left to right... that it what it is like)
I think the model does need
1. Revolutions so you can scrap one social Policy for another (possibly at a 2 for 1 rate or something like that.)
2. Variable costs... the cost of a Social Policy should probably depend on how many other Social policies you have. (it should probably also depend on how big your empire is)
#2 would probably relieve a lot of the concern... if it is cheaper to get "Universal Suffrage" if you DON'T have "Aristocracy" then it makes sense. (But that shouldn't be a specific counter, it should also be more expensive to get "Universal Suffrage" if you have "Free Market" or "Monotheism").
It would also stop the 'racing through the tech tree' feel if the cost was dependent on the size of the civ. (so small civs would be just as or probably More culturally advanced then large ones)
You can't 'be a Tyrant and a Democrat'... you can build a society that has some of the advantages of Tyranny, and some of the advantages of Democracy.
I think that is definitely reasonable
Especially since 6 trees=game win (ie Culture pumper)
10 trees=available...
assume the Average Civ actually only gets 3 trees by end game.
If it is effective to 'stack up' policies in the same Tree (ie Universal Suffrage+Free speech+Emancipation all worked best together in Civ 4... Just like Representation+Mercantilism+Caste System+Pacifism) then most Civs will only be working on 3 of the 10 trees. Which may provide some imaginative Societies, but the tech tree provided things like that already.