You summed up my version of this problem pretty neatly. Many people complain about there being too many specific items and that Pokemon is "crumbling under its own weight", but I disagree. I feel the opposite. I think that they aren't doing anywhere near enough with all the things they have. If certain Pokemon have items or MT moves that are exclusive to them, they need to actually do something with them in the games as opposed to just leaving them somewhere without ever being mentioned, or locking them behind Battle Tree shops or something similar. There is a lot of potential for things they could do with everything they have in the games, but most of the time, they aren't doing anything with it. I don't think they have ever handled all of these things well in any past game either.