Here's what I've discovered as a healing templar today, though granted my sample size is still a bit small.

Mutagen (Reso Staff HOT) will only crit on myself if I have Inner light (17%) crit up.
Cleansing Ritual (Supposed to be 1 heal every 2 seconds) does not heal over time, only once, and never crit.
Grand Healing (Resto staff #1) never crit.

This is on myself.

On others, I get crits occasionally. I'm trying to find some way to test %age but I haven't gotten an addon that will separate heals on myself from heals on others. Currently I'm using Combat Log Statistics (CLS).

As a templar I have been testing with Innerlight up and then my passive (30% crit on allies, goes up when lower health). From what I gather, I have 0% crit on myself unless I am using magelight, or it is extremely small.