hey there, it might be only me this is happening to, but i have scoured the landscape of skyrim and killed a hoard of beasts for their pelts and i notice that if i go back after a while its still as desolate as i left it.
that said i see the reason to why caves are buildt like they are, once you cleared them youve cleared tho some respawn in some caves would be apreciated. them but the open landscape shouldt always be teeming in my opinion

any opinions?

I think that the wildlife should re-spawn in 2-3 days.

Wildlife or caves or whatever should take time to respawn to avoid grinding. Not that it matters its a sigle player game.
Bt i personnally would be pissed if i cleaned a dungeon left some gear come back less than 48H afer to get the gear and had to clean the place again, tis was a pain in oblivion, and a never ending source of richness