Those 3 classes are the Cleric, Elementalist and Tempest.
Cleric: Oh my goodness, you finally got a support character in an mmo again. Setting up opportunitites for other players, getting them out of a bind and buffing them helping them doing their job better. This makes me extremely excited for this class, seeing as support is by far my favorite role in RPGs as well as MMORPGs. While he has access to healing too, but I am far more excited about his support capabilities.Of all the classes shown so far, this one is the one that interests me the most.
Elementalist: Man it is nice to see dedicated crowd control characters again ever since WoW decided to make crowd control a fire and which keeps an out of combat without fail during its 50 minute duration. Furthermore, using some of the skills seem to have an impact on the environment too. Using the ice skill can turn the environment into ice which makes terraforming a lot easier. Finally it will be interesting to see how other characters can interact with the affects the ele puts on his or her foes. How will others be able to interact with burning or frozen. Overall seems like a very interesting class and one I will definately play assuming I get the game.
Tempest: Meh... looks like a highly mobile dps but with lightning. Not really my style and I couldn't care less about this class. Everyone else seemed very enthusiastic however.
What do you guys think of these classes, do you share my opinion, do you disagree? Which class interests you the most of these, or perhaps none interest you.