The offhand issue is an issue but there are several decent options,
Librarian's Paper Cutter had decent itemization for a healing offhand, and there was a heroic BC dagger with two sockets and some other non-useless stats that were at the time considered best for this. You also have to remember that the second earthliving enchant does give additional healing. Essentially they were comparing the offhand to your shield slot, not mh and at the time there were no shields that gave greater spellpower benefit (not sure if this is still true.) Earthliving weapon isn't doing much for you but you're not running dual earthliving with a glyph to improve procs either. The idea of the build was in part to be able to throw a chain heal and proc earthliving on 3-4 targets at once, speading the hot around the raid.
It was a really narrow build, the only spell you cast is CH. It had a lot of things going against it. At best it was considered at the time to be a one trick pony that tried to brute force out additional spellpower in order to make chain heal better. It was also supposedly boring to play, since you only had one spell to cast. As of now I imagine the build's dead since I can't even find the thread for it on elitist jerks.
edit: finally found the thread on EJ's they say the build's dead since 3.1 when ancestral awakening started counting overheal.
here is the thread if you want a look.