My experience with HG is pretty much limited to single player HG:L so far, so I'm not quite sure what to do for a solo Guardian in HGG.
I was kinda planning a build like the following
http://www.hellgateaus.net/planner/#Guardian,55,50,0,v1.0000160039000000990406000001000611,000004004440040, but I'm unsure about how viable that is. My thoughts are roughly as follows:
Spiritual Strength 6/7 because the feeds are insane
Shield Bash 3/10 because I need shield turn
Shield Turn 9/10 because stun locking mobs is a good idea
Aura of Defense 9/10 because I want to survive
Aura of Renewal 9/10 ditto
Aura Stability 6/7 ditto
Grand Aura 4/5 because if you invest that much into auras, you might as well use them to the max, also it should help with
Challenge 6/7 come to daddy!
Denounce 1/10 because it gives a nice boost to taunt strength
But what do I do about DPS? I thought about putting one point each into Sword of Reckoning and Anchor (which should combine nicely with Challenge). But can I combine those two, i.e. can I spam SoR while being Anchored? Does Challenge work on end game mobs? And is that enough, or do I need to sacrifice some defense (which?) to put more points into offense (again, which?)
And what do I do about mobs with the Regenerating ability? My experience from HG:L is that my Guardian just plain didn't have the DPS to kill those, and neither Poisoning nor Shocking them seemed to make any difference in keeping them from Regenerating. Is that still the case in HGG?