Leveling through campaign again and again and again....

leveling is a lot more fun when you level withthe skill that you are gona use lategame asap
often i even drop the leveling gear just to struggle a bit more
actually having to fight enemys instead of killing them before they can even hurt you,can be a lot of fun

like ppl already have said,new leveling ways will become "boring" very fast

but why not to create several ways for leveling, and its up to you which way you decide to go for new character? i can imagine poe where i can choose whether i go through campaig, or through delve or whatever.... and this will be definitely less boring than current situation.