It has a bigger battery but it mostly evens out due to the larger screen.

I think Apple is very keen to ensure that you’re able to tell when someone’s wearing an Apple Watch, and they’re happy with the general silhouette of the watch as a result.

Personally my guess is there will be a redesign of some kind next year, but I think the folks who are holding out for it or excited about it will be disappointed by how Apple Watch-y it remains. Think less iPhone 8->iPhone X, more iPhone 14->iPhone 15. And that will include the Watch remaining square and, subsequently, probably the bands staying cross-compatible(barring some other reason to change the design I’d be unaware of, like saving on internal space or something).

Not trying to be snarky, but are you sure there isn’t something wrong with your phone’s battery, or have you not updated iOS?

5 hours usually leaves me with 40-50% depending exactly on what I did that day.