I know the implications of Bless with / without source cost, but the thing is people will have even less reason to be defensive if they can bless any surface at will to heal themselves or restore armour. There will also be less reason to play undead. Even if they are healing enemies too, they can remove points from constitution (if they had any there in the first place), Geomancer or Hydrosophist and put it in STR / INT / FIN / Warfare / Scoundrel / Huntsman to deal more damage, thus compensating for the healing of monsters. Bless needs to cost at least 3 AP if the source cost is removed.
