How about 2 portals per map

If you die you get a second (final) portal. Respawn all mobs but if you reach your corpse get all of the lost exp back (Yes exactly like in dark souls). If you die in the second portal lose all exp and map bonuses.

If you die in the seond portal before you recover your exp, you lose double the exp (because you died twice in the same map).

This sounds infinitely more fair to me that what we have atm and it creates options and decisions for the player.