If we don't get a new Tank and Healer as the next new Jobs for 5.0 then I'd be extremely disappointed.

People don't like to Heal even less to Tank in MMORPGs so people think that those who Tank don't need more Jobs to do so (as per Yoshi P's statement that Tanks will still tank in 4.0), well no.
It'll depend on how much they'll add to the current Tanks, tweak and change them to please the existing, yet slightly drying, Tank population.

Also if we get 2 new DPS ... well it'll be fun time waiting for a queue.

I really wish we'll get a new Tank&Healer, the current ones deserve to get something new too, not just DPS.