i think outside of western barovia, perma-maxed dungeons isn't a...bad idea.
im never going to, say, har'akir with the intention of doing any min or even mid-level spawns. the effort of getting a group together (ie a mage, a rogue, a fighter, myself, and maybe another friend or two cuz its an outing not just an xp grind!) to get little xp or loot just ain't worth it! once you're in the realm of carefully* configured parties the whole disparity thing is kinda pointless
it makes more sense in western barovia, though, because as the start zone there's a lot less organization among the adventurers so you might go with a very subpar party and having a lower spawn might be what it takes to have a do-able adventure!
however, that said, it's really not that hard to get xp even now. even if you don't no-life it, as long as you do some good dungeoning every now and again with a good helping of RP, you should be well on your way to those high levels and enchanted equipment - and the heartbreaking realization that all those levels don't really mean anything and you really shouldn't sweat it too much
*by carefully i mean 'yeah we got all the roles we need lets goooo'