My main way of dealing with the issue of keeping companions alive in Oblivion was to use the console not to resurrect them, but rather to multiply their health by 10. I'm just about to take Lydia out on our first quest together; I expect her to hold up pretty well after being buffed from 181 hp to 1,810.
Great idea! What's the command for that?
Open the console and click on the companion. Sadly, unlike Oblivion, it displays only the companion's formid and not their name, so you won't know whether you clicked the right object (as opposed to, say, some fog in front of them) unless you use some "getav" commands to inspect them.
Anyhow, in the console, with the companion selected:
getav health ; to get their current healthgetbaseav health ; to get their maximum healthsetav health xxx ; sets health to xxxmodav health yyy ; alternately, this adds yyy to health
Unlike Oblivion, it seems that using these commands to increase current health to above max health will also increase max health automatically.