dont forget if ALEXANDER is in the game its going to be very hard to ally most city states
For most civs, ally status is quite important, much much more valuable than friendship status. But there are a couple exceptions, Siam for example. Portugal does not even need friendship for her UA. So Portugal has the strong advantage that she can ignore Alex -- just as long as he does not win by Diplo.
But I don't know that I think much of a UA that only counters one civ out of 43!