Wasn't there a plan in TurtleWoW to change the channeled pet heal into a single cast instant heal hot back then?
Or was that done in lightshope? I don't know exactly, but this would stop the downtime to heal the pet while all other classes pump out damage.
Also having such a short heal range is bad with channeling... you always have to run to the pet or call it back and wait till you reach it and then stand still until 1 or more channels went trough until you start your rotation again.