Why Rebels are so BROKEN? (What about the rest of the characters...?)

Other than making them strong, they also want to ride on the hype of the new movie.

This time last year (or a bit later, around EP7's release) we got the bunch of Finn, Rey, Kylo, Phasma, etc., now we get those guys and that trend will probably go on well into January. This way, they a) inspire the mega-whales to pay again; and b) may inspire those who plays this game less competitively, may be less willing to pay, but get overhyped by the movie to buy those fancy new guys. Two in one.