Definitely a lot clunkier on 3ds than Wii U, and yes, shame about the lack of straightforward online play in comparison to its future 3ds counterparts. But coming back after playing a sizeable chunk of Gen and 4U, the early game is somewhat enjoyable. Avoid bow if you used it in the latter; the controls have been swapped and I still haven't seen any option to change it back. Affected me more than I thought it would at the time. Have not currently reached proper underwater hunts, maybe I'll update it once I've tried one. Regardless of the high contrast in comparison to Tri visuals, I feel like I still have to strain a little when underwater. It'd be nice to get further into Village Rank though.
I used to complain of the gathering RNG not being kind. I think that's a universal thing.

Good plot. Wonderful soundtrack that I still listen to. I used to wish there was more post-game content, but I've been shiny hunting instead of battling since completion. If you walk around the region a bit more then there are side quests here and there (I just haven't done them). I like darumaka.
I tend to feel excessively nostalgic and gloomy at things like server discontinuations, so with the imminent closure of 3ds servers, it makes the mystery gift music all the more painful to listen to. But maybe there's the possibility of a remake. Not that I would watch too closely, but it would be nice, I guess.