I like the strong rebell citys - as Athen/Sparta you need more time to unite greece, as in ancient times there were many independent and powerfull city-states beside them!
So itīs a greater challenge, and beside it maybe avoid them from becoming to easy and ahistoric a global power (particularly when controlled by the AI), as their units seem quite strong.
I would not remove Taras. When iīm playing a greek or balkan faction i want an enemy in Italy to fight against.
btw. removing Taras and replacing it with the city of "Croton" would be a good suggestion.
It was mightier and more important in that timeframe !