While the transition between water and land is a bit laggy and awkward, I do like that it's seamless and doesn't require any additional action from you (e.g. activating the boat or anything). Also, the khyek's sails are really pretty; I love the way they shimmer. I hate having to spell "khyek" though; I always just want to write kayak.
I do like the fishing mini game. It's nice and relaxing. And I love the idea of having fishing heroic encounters! That giant sea turtle coming out of nowhere to kill you is bullshit though. Also, ultimately I'm not sure what the point of having all these fish is, as there only seem to be a few rare ones that are used for crafting and everything else can only be turned in for elk tribe reputation? I'm kind of missing a reason to keep at it, other than the daily quest.
Not sure what I think of treasure maps. Asking people to identify the correct spot based on an environmental drawing in a zone that consists entirely of samey-looking ice and rocks is a bit of a pain, not to mention that everyone will just look up a guide on the internet anyway. That said, the treasures often seem to be hidden away in such a manner that even if you know the rough coordinates on the map, it's still a challenge to figure out how to get there.