Well, it was stated long before gaem release that guardians wouldn't tank better then other fighter classes. When I looked at the skill lists it looked like guardians would get more skills to protect the group, so I figured that would be their main purpose of the class, and the thing that made them special.
The issues of higher level spells not being good enough is on every single class board I've read, so this isn't a guardian issue.
I guess many picked the class asuming it would be like the EQLive warrior and I feel sorry for those people. I've seen guardians who think they are the only maintank and other that realize other fighters do the job jsut fine.
Just my 2 cp
BTW: Not playing a guardian, not even a fighter, this is just from personal experiance. I don't say they are good or bad, just saying that some people might have missunderstood how classes are soposed to work. I see this in other places too, like the cleric/shaman/druid concerns.