I humbly suggest that any game that breaks unless players do X, Y and Z every time is not a game with the sort of flexibility and expansive nature that RPGs are said to have.
I'm not talking about a group that's made up of cloistered clerics wandering into the Tomb of Horrors. There needs to be more give in the system than saying "well, of course you died, you didn't have a cleric!"
That goes for any game. Even 4E's explicitly role-based system is better, since the "leader" role can be taken on by clerics or warlords (and soon, other classes), and they play quite differently, which means that someone at the table doesn't "lose" and is forced to play the cleric in order for the game not to break.