As a hero helping in lowbie fights sure spamming it wins the day,
In most other situations, or if there is anyone around that can
harm the acolyte it can be oh so bad. Also look into how many
acolytes altruism themselves to death.
In the end just play one and see for yourself, while you might still
feel it needs to be tweaked, i'm almost 100% sure you will have a
slightly different view. Might as well make out of range healers
unable to cast spells. They might only be able to cure one thing
at a time, but they also do not suffer the effects.
If you want to tweak something you'd kind of have to make it where
any out of range aid of any kind would be less effective.