The information will be coming on Thursday. We have quite a bit of tidbits from Logan in the book. Hunter has a wonderful article. ( http://huntersinsight.wordpress.com/2011/01/03/guardians-of-guild-wars-2/ )
My worries are that people are going to be too giddy over the ability to heal. People crying over the fact that guild wars said their will be no super support class could start the arenanet lied to us cries.
I think that the healing will be minor and very energy intensive while knockdowns and damage reduction will be a little lighter on the energy bar. They may have some sort of aura effect like the paladin of Diablo 2. Much of GW2 is reminding me of Diablo 2 (energy potions...sigh).
I can see a guardian being a sleeper profession at first, with the first wave of players playing it like a warrior monk who tries to heal. Then the player base will learn to play gw2 different from gw1. Knockdowns and weapon spells (possibly) and auras(possibly) will work well with the other professions (especially the rogue that originated from the assassin).
This is, of course, all talk and speculation, which I typically avoid.
Any thoughts or ideas?