This is something I don't get. Yes, Mp5 is a healer-oriented stat, but that doesn't mean a healer gets any extra regen from their new loot.
Say you've got one healer and a caster dps - both of them are using a 550sp weapon with 50 crit rating and 25Mp5. They run an instance and a 650sp 50 crit rating 25Mp5 weapon drops. So suddenly everyone goes "omfg healer wepaon!!!111 it got mp5". But why should the healer get it first if it doesn't give them any more Mp5?