I think it's hated because they got rid of day/night/date.
It's hated because there was no way to get your favorite Pokemon whom you trained and grown attached to for half a decade, and have them in the new game because of 2 terrible system changes that no one liked or asked for.
That and there was no way to get every single pokemon until a remake and console version later unless you gamesharked.
--
Nice catch BlAcK TuRtLe.
But too bad your ass got SAAAAAAAAAAACKED.*tackles*