I'm not sure why people like post-game stuff so much if I'm honest. Maybe if there was an arcade-like mode for the end of the game, perhaps an "infused depths" of sorts, which has /beastmode on obligatorily. You then fight room after room of enemies, each which can be from any area in the game, following basic guideline to make rooms fair, such as "5 basic enemies (eg, slime, brawler bot, wisp) and 1 heavy enemy (eg, boar, hydra, yeti)", "3 basic enemies and 2 heavy enemies", "1 elite heavy enemy and 2 elite basic enemies", "2 basic enemies and a scaled down miniboss" sorta stuff. You fight a miniboss at the end of the first floor, a proper boss at the end of the second floor, and a shadow creature on the third, which can take attacks from almost any boss.
It sorta follows an arcade-like pattern, but you keep all your gear at the start and the end. I wouldn't mind that, but only if it's got different enemy combinations to normal Arcade mode. All in all I think arcade mode needs a change such that its easier for newbies to get anywhere beyond the first floor. It kinda puts people off.