Hmmm, the great use for tech 'flavours', which I can see, are twofold.
Firstly, it is another way of getting AI civs to adopt a wider range of government types, by actually making them LESS likely to pursue certain Gov. Techs over others!! Decided which ones a Civ will favour should depend on that civs Preferred/Shunned Gov. type-for a start-with the rest being filled in on a purely historical basis! I would'ne set the flavour bar TOO HIGH, though, but just enough to create some governmental 'disparity' between different civs, of different culture groups

!!
The second, related, use for flavours is as a part of my idea to introduce a more wide-ranging religious element to the game! By adding a whole host of different religion types, from Polytheism, to Monotheism, to Eastern Religions and then giving them appropriate 'flavours', you could have all the worlds religions well represented within the game, whilst still allowing room for, as an example, the Chinese to become Monotheistic, or the Germans to remain as strict 'Polytheists'

!
Anyway, just a few ideas for those of you who'd like to test them in a mod (hint, hint

)
Yours,
Aussie_Lurker.