Maybe the world is too big for the amount of stuff to do in it? A vast but empty world will do nothing but hamper the experience. Not saying XCX is empty, but maybe there's quite a lot of filler sidequests of relatively low quality? I don't know. Heck, I'm not sure if reviews have even claimed that. IT always make me chuckle when people complain that "media is biased against *insert genre/IP/company* here" though.