Nearing the end myself after 45+ hours - by "end" i mean catching 240 Pokemon, not getting all of them to Level 10 in the Pokedex. I'm feeling a bit frustrated with the randomness of the distortion events and some of those Pokemon, and finding all of the Wisps was super tedious. I wish that there was a better way to keep track of the Wisps you've found, you know? Like if they were numbered somehow. The distortions themselves are cool but it's annoying that there's no way to tell when they were happen and that even when they do they might not have the Pokemon that you really need.
Besides those couple of things, however, this game is great and I've loved my time with it. Some DLC would be welcome.
The only time either distortions or wisps got tedious for me were:
1. Finding the very last wisp overall was annoying because it was in the icelands somewhere not spottable while flying around (it was underground in an area I checked a few times but never got close enough for it to appear)
2. My last missing pokemon was a fossil pokemon and I just flew around waiting for a distortion to appear. Caught ONE in the very next distortion, couldn't find anymore, and ended up having to farm Pokedex tasks to hit level 10, evolve it, then level 10 it again.
3. Some of the baby pokemon just needed to spawn more. Having a few more trainer encounters where at least you could see them to get the location data in the Dex would be nice.
As far as DLC is concerned, I would love to see ones where distortions or space-time rifts brought additional legendaries (although hard to do post-game since basically the rifts should stop):
1. Bring RSE legendaries and throw the weather out of whack in regions with other odd Pokemon showing up where they shouldn't (bright and sunny in the icelands, etc.)
2. Set the birds/dogs loose to just roam and have to chase them down, would have to use feather balls to hit birds in the sky or dogs moving fast.
3. Since competitive isn't a thing, bring back mega-evolution forms as mega bosses to battle and obtain the stone to do mega evolution forms if you beat them. Hide them all over and find/beat them all to enable mega-evolution.
4. Have other ultra strong trainers drop with their corresponding teams for those that want more trainer battles. Elite 4 members, Cynthia, etc.
Lots of options, but it also might be nice to wait for a sequel to do some of these.