Well, I did not actually edit any moveset at all( meaning, that they will learn the same moves through leveling you would expect them to learn). I just edited more useful moves, most of which you would only get through breeding.
I did this, partially, because I have some unusual starters (Abra, Beldum and Tyrogue, for example) which are utterly useless, if they are not bred. Abra would only have teleport, for example, which, of course, does absolutely nothing in a fight. So I gave everyone something, they usually wouldn't have, unless bred.
Of course, this might seem powerful, but I am certain, that the moves will "lose" power later in the game (for instance, Abra with Firepunch might be nice in the beginning, but not so much later in the game, as Alakazam simply lacks the physical prowess for those moves to be effective).
Also the NPC-Trainers have modified movesets as well (at least some of them, not every single trainer of course).
Kai's Mankey, for example, knows Close Combat - a move it would only have after being bred.
Thus, I don't think that they are too powerful. Powerful for sure, but not too powerful.