Leave them as it is, it would give you 'I LOVE BEING CHALLENGED' players something to do and let us crap players use them to win, its not like its a MP game. lol
If it was a MP game, then go ahead and balance, but its a SP game so leave it as it is.
Well, i tried the Yor with the default abilities, i have no idea where you got your 'overpowered' idea from, they are not over-powered at all.
Hell, i even cheated with the money and the AI still out-produced me.
within 2 months the AI beat me with a cultural victory.
they colonized a medium sized galaxy in 2 months. (they were Human)
Its a pity there is no strategy to this game, its just basicly, rush to the planets and pray you get to them first......if you don't game over....kinda stupid if you ask me.
But the Yor are NOT overpowered.
The AI must customize itself to challenge you, so the more you can produce, they produce faster, the more you can research, they research faster.
Lets just say, in 2 months, they had Trade, Advanced Trade, Planetary Invasion and Master Trade. (it would be impossible to do all these in 2 months.
How does the AI do it??