I know I'm late to reply, but the chest in the shop transfers between characters. If you get an epic drop for a different class, you can put it there, make a character of that class, and when you get to a high enough level it'll be there waiting for you.
As the game progresses, higher level enemies will be added, it's just natural. As-is there's no real reason to grind to level 20+ or whatever
Item abuse is already handled by potions having a cooldown. I get that you have a weightgain/fat fetish but jesus that would be an unbelievably unfun mechanic