Water is SO HARD. Even games that have a heavy focus on water such as Raft, Subnautica, Stranded Deep, etc have some severe limitations that work for their concept but would fail completely on a fully-destructible game like 7d2d. Add to the challenges the potential for griefing that water presents which must be taken into account in a game that supports PvP like 7d2d does.
So I personally don't expect anything but mild water improvements going forward. I think water + crafting + fully destructible is enough of a challenge to make a whole game around it.
Although I also don't have any great expectations for the announced "water overhaul" (you explained the limitations),
I still also hope for that "go fishing" thing which was asked for many times thoughout a whole bunch of alphas now.
It just fits too well into that survival aspect of the game, that you would be able to craft a simple fishing rod to have some food supply.
Not necessary though, you have enough options to get along now, but just for the total of the concept, I second his thoughts.
Great opportunity to create some kind of mini-game, which contributed to make many "AAA" titles like Fallout, GTA,.. so popular.
Lockpicking in Fallout is simple but feels great beacuse it's fast achievement/succes with using some skill. Watching a counter going to zero in 7d2d is just a missed chance in my opinion.
GTA has all that small cool stuff like playing billards, bowling,...all small simple game-in-the-game stuff which adds to the fun.
Going fishing could be one of those if it's done correctly...and there is much more stuff, especially in a fully destructible world, what can be used the like.