Lesser Minions = Easier Control = More microable.
If Damage has overall been increased, minions have actually become stronger since beta 3.
Then why wouldn't I want to always go for 10 healers to make me invincible?
Because preists have a cooldown of 10 secs for heal, and after being healed by a preist, you cant be healed for another 10 secs (something like that). And if there were 10 there should be lower healing rates etc.