I just looked at the videos and it's really hard to tell. Seems to me that the guardian had a good ability to kill and to stay alive. I think we'd need to see them in PvP or in side-by-side PvE comparison to really tell.
The thing that I expect though is that all professions should be roughly equal on survival and damage. Here's how I figure it out... Ever played a priest in WoW? It had great spells to heal and protect, but was really terrible for damage for at least as long as I cared to play it. Meanwhile, rogue was great at damage and poor at staying alive. Druid could do it all, and could even flip between roles. So everyone played druid and paladin because they could do everything well. It was a mess, especially in "single-player".
Now imagine being stuck with the profession that you like, but finding out that it's sub-par. Imagine being a guardian and ending up not getting as much rewards and XP per hour because you don't kill stuff as fast as other professions. That would be terrible, right? Oh sure you don't die, but neither does the warrior with his high health and self-heal.