That certainly explains some things. Since all the mods are kinda bleh for right now I can definitely see why this class specialty would be better set for DPS. I will take a look at the guide for now and future reference.
Ehh no. I was not soloing that H4 (I learned THAT one the hard way earlier on a couple H2s), but I could tell not long after starting in I was being taken out far too easily for a tank. Though it didn't help the healer initially went in ahead, instead of waiting up for all of us to arrive. Since there was another team right there doing it as well, he got out okay.
I digress... I'd go in stealth and send out a force wave or sneak attack one and draw attention. Then the healer would generate threat and force the DPS guardian with us to have to redirect them. We had to shift tactics a bit to succeed, but we did. Essentially resorted to "DPS-gang-banging" single big enemies one by one (which seemed to distract everyone else), walling them off so they couldn't go after the healer, then took out smaller ones after. Worked out well enough I suppose.
TL;DR: No matter what I tried, it just didn't work out for "tanking".
The only stat in the tree I'm a little iffy on mental fortitude, if endurance is ill advisable later on at level cap... The arguments I've gotten is that it might be redundant simply because with everything else that boosts endurance by level cap, you're basically not doing much beyond the point of diminishing marginal returns and that those talent points might be better served elsewhere. *shrug*