Overall I think that, although Alola as a region isn't that exciting, this has turned out to be my favourite pair of games in the franchise. Mostly this is by virtue of the excellent quality of the games plot, characters and dialogue compared to previous instalments. One thing I've noticed though, is that now that I've completed the main story and post-game story I haven't got much desire to keep playing or even to restart. I wonder if this is a downside to having a more plot oriented addition to the series?
I'm curious as to your thoughts on why Alola isn't an exciting region. I personally love the atmosphere - how Pokémon are more a part of everyday life beyond just battling/pets, the tropical environment and customs, and so on. In many ways it seems like Hoenn without the annoyances of HMs and "7.8 Too Much Water". They did a great job of giving the region its own cultural identity. As I've been working on my Moon playthrough, I do see where you're getting at with the replayability though. Don't get me wrong, once you get past the first couple hours, it picks up a lot, but those first few narrative-heavy hours are kind of a drag. I wouldn't go so far as to say they'll prevent me from replaying the game again in the future, but it does take a bit longer than most Pokémon games to get into the action.