That could work, on paper at least. But I still don’t see how it would be that much of a boon. Okay, so you get true health, but it is still considerably less and less reliable. I mean, at a certain point, you get by on temp health over the whole map, anyway, and only use healing as convenience, not necessarily because you need it.
I would also see problems with Pyro Sienna and beam staff, since this is, arguably, one of the few builds that can benefit from health on crit, but that’s just a minor aspect.
The poinit is that it really doesn’t matter if it is true health or temp health: If it doesn’t proc at the right time, you don’t get any. There is no difference between temp health you don’t get and true health you don’t get.