I feel Kato is a strong writer, but I'll admit he is someone who works better on collaborative works than on his own. He's a bit like Nojima in that sense that he needs someone to reel him in cause he tends to want to over-complicate everything. For instance Kato is responsible for most of the Zeal arc and the second half of CT. He also worked pretty well in VII and Xenogears. With that said I trust him more than Nojima and I feel that his work on the DS version of CT shows that he's mellowed out a bit since the old days. I would love to see him come and work for Square-Enix on a non-MMO project (he still writes scenarios' for XI and XIV for instance).
I don't really hold the absolute hatred of CC like some Chrono fans do, I actually like the direction it was going I just wished it was more focused and less pretentious it reeks of an auteur game where Kato was pretty much given unlimited authority to do as he wished. That's not to say its bad and doesn't address some great issues and have good writing but I kind of feel at times that Kato kind of lost track of his point until almost the end. The game is pretty anvilicious about its themes as well even though some times it doesn't make much sense in hindsight except to make a point but its kind of shoddy writing. I feel that if the game had a much more narrow and focused cast and story it could have been a brilliant game.
The reason he gets hated on is because he took a game that was close to an impressionable generation and kind of turned it on its head. I doubt VII fans would have reacted any differently if Advent Children had been about a new cast of characters learning that not only did Cloud and Co. die in the intervening years from Don Corneo rising up as a the new leader of Kalm, which had become the new military power, but also had made the world worse and would have been better off just letting Sephiroth have his way. That is probably the closest analogy I can think of to what happened in CC for CT fans. Some fans simply ignored it and played it like it wasn't connected to the original, others reviled it for ruining their favorite game, and others appreciated it for what it was.