Yeah, I can see it being a problem if you only play RAW. But since it seems like there's a bit more emphasis on Rule Zero this time around (my personal impression only, please don't debate this ad naseum), that'd quickly be over-ruled. Though, even if you did...
essentially, you're trading an at-will to give an ally a basic attack. If that's the case, why didn't everyone just make fighters? And, since there's more than one baddie on the table, you're letting the fighter beat on one guy, while the rest of the monsters eat your face, unopposed.