To preface this, I am not one of those people who hates this game because of the fanservice. In fact, that is actually one of the few things I like. That said, I do think the fanservice does take away from the story they are trying to tell.
Aside from the soundtrack there is little here that I do not hate.
The combat system is tedious, slow, and painful to engage with. The world exploration is fine but made tedious by the collection point system, which like many things is explained only slightly. The plot to this game is, in concept, quite good, but is held back by its protagonist. For the story it is trying to tell, Rex is at his best only a mediocre fit for the role. He has no growth, he has no sense, and his character moments do not sell the game on his realism as a character. Several character moments happen without the proper setup and then are gone the next minute. Possibly the worst aspect of this game is that Rex has literally negative chemistry with either of the two female leads.
It is difficult to believe that the Rex in Xenoblade 3 is the same person as the Rex in this game. Possibly the worst protagonist in a JRPG I've ever played.