There's one issue, that bothers me: Dying should give back at least some PP.
It feels incredibly frustrating, when your team (especially 2 member ones) has used up (almost) all PPs for the damaging moves and you die (i.e. you messed up or got super unlucky at a bad time). Then it doesn't matter how many lives you still got - you don't have a chance to get to the shrine.
IMHO you should at least have a chance to win the 3 required battles - somewhere between 5-10 PP per move.
I know, you can play around it, have a bigger team (4 members), better PP management, change mons more often, etc. ...
But when you mess up - the time you spend burning through the rest of your lives is just having a bad time. :-(