This came up in a discussion in another thread, but I think deserves it's own feedback thread. These tiles, I think most would agree, are generally weaker then other tiles. There are fewer things you can build on them, they take up space, and the only real value they hold beyond having access to a couple for the small number of structures is in adjacencies, which more incentivizes you to have them outside of your borders on the edge then inside them. This problem also exists with ocean tiles - there is no niche for a high water city to exploit.
This feels weird both on balance reasons, and history-representing reasons - especially the freshwater tile sources are the lifeblood of most real civilizations. They are built around lakes, around rivers, around water. That not translating into the game is strange, and I believe steps should be taken to make these tiles more beneficial and give unique things that can be done with them. The only way this is really represented in game is the freshwater mechanic, which only matters for your city center and thus you want to do the minimum possible amount to achieve it without wasting space inside your city on otherwise useless water tiles.
There's lots of ways to do that, and I think others putting their ideas in would help. The one that is most obvious to me is to add a couple new resources, intentionally tuned to be stronger then most resources, that are exclusive to lakes and/or navigable rivers. What those are doesn't matter, but part of what makes these tiles weak is that they have no resources. It makes it awkward to route rural tiles through them and their lack removes a potential push towards settling on them. There's lots of other things you could do - maybe navigable rivers and lakes should give an adjacency bonus to nearby tiles? - but in some combination of ways, I think it's important to encourage their active use, instead of avoiding them as much as you can get away with.