I guess I'm supposed to answer this one...
As a Consular, Willpower is your mainstat, it affects your crit rate and your bonus damage. That being said when playing a tank yes you're going to typically choose armoring mods that are higher in Endurance than in Mainstat. At later levels you also have secondary tanking stats to worry about though, Defense and Absorb. At end-game, typically stacking Endurance over your mitigation stats (Defense/Absorb) is inadvisable.
Shadow Tanks have tools to excel at both tanking single boss enemies, as well as packs of multiple smaller enemies. That being said, of the three tanking advanced classes, Guardian, Vanguard, and Shadow, by selecting to play a Shadow Tank, you've decided to pick the most challenging tank to excel at. As far as getting destroyed during a H4 mission, were you trying to do it solo, cause that'd be a bad idea. However, tanking at lower levels in general is pretty ineffective. While that is true for all the tank classes it is especially true for Shadow Tanks, you wear light armor and get shredded easily early on and you don't get some of your best tanking abilities until your upper 30's or lower 40's in levels.
Honestly, I highly recommend that you level as DPS and learn to Tank when you level cap. Leveling just takes much longer when you're leveling as a Tank and especially with Shadows you don't feel very tanky until much later in the levels.
Anyway, I wrote a guide for Shadow Tanks that is a few months old, but should provide enough of the basics... http://www.thewalkingcarpets.com/for...tanking-primer