If none of the characters we have now ever die, then how are we going to take whatever new threat that comes our way seriously, at all? Because they exposit that we should? Because they blow up towns that we've seen blown up by lesser threats? Make us feel the threat.
Imo, that's not the problem of characters dying or surviving, but rather the age old problem of ever stronger escalating threats (i. e. threats with a stronger and stronger "power level"). We'll have been squashing world-ending foes left and right, esp. at the end of EW. So the EW post-game needs to make a new start with new dangers that are somehow equally (or more) threatening than a re-enactment of the literal Final Days if the plot isn't depowering us somehow. Technically, every regular dungeon visit afterwards shouldn't be threatening at all (ignoring from a player pov of "everything is faceroll-easy lolz"), unless the Final Days will uncover some age-old sealed dungeons with somehow more threatening stuff in it.