I think the bears' punchiness and sturdiness is fine, but their frequency feels like a difficulty crutch and they could really be a lot more interesting. I saw a suggestion in the 1.20 spawn rate complaint about visible dens and bears sticking near them which would be neat.
What I really would like to see is a buff to the prey species though, obviously we don't need all of them to have a bear's aggro but it'd be nice to see a moose body a bear for being too angsty all the time.