I guess it depends on where you are in the game.

Currently if you beat the final boss there really isn't an event linking to the next biome yet. Maybe a hoard of boar size spiders that can climb over anything?

I don't mind feeling stronger and safer as I progress... frankly the last thing I want is to feel is that upgrades and progression make you feel weaker.

Then comes in the balance factor of having someone lower level join your world and basically getting wrecked constantly.