There was at least a bit of discussion about New Job ideas for tanks (Blue Mage, Samurai as tank, Gunblade/Garlean themed Tank, Red Mage as Tank, Dancer as Evasion Tank), but it's much harder to focus discussion on new Tank ideas then changes to existing ones. It's easy to see the problems with Paladins or the current Tanking meta, but it's harder to envision an entire new class from start-to-finish. As players, we don't know exactly what kind of mechanics are feasible from the game engine, and we lack a lot of knowledge about future encounters or development features. For all we know, 5.0 could turn the entire combat system into Rock Paper Scissors. Building new jobs from scratch at anything more than a surface level is difficult, and even harder to discuss. There's not too much to critique if all you can reasonably say is "I want a Garlean themed tank".
It's far easier to give feedback on existing jobs and abilities then build from nothing. Even for DPS you'll see more discussion on edits to existing jobs then the addition of new ones. We can't give feedback on things we don't actually know anything about. Which is also why I'm disappointed by the lack of information on the supposed class revamps. I would love to give some feedback a little bit earlier, but we have nothing to discuss in that regard.
As I mentioned earlier, I am disappointed by the lack of a new Tank/Healer, and I was especially disappointed by their poor arguments. I understand they were just trying to assuage the (very real) concerns about queue times, but it felt like a bit of a slap in the face. During the stream, you could tell a fair number of people in the audience were disappointed with this part of the announcement. Most people (including myself for the most part) have cooled off, but I think some disappointment is perfectly appropriate. New Jobs/Classes are always one of the most exciting part of an expansion, and a good number of players feel a bit left out. It was kind of inevitable since Heavensward added three new jobs and this one is only adding two, especially since Ninja came out shortly before Heavensward as well.
That said, hopefully in the next expansion we'll have new Jobs to be excited for. If the balance updates are phenomenal, we'll have more room for expansion. At the very least, they won't have that excuse anymore. It's just very long off into the horizon right now, and discussion of possible new Tanks/Healers is basically pointless for the time being. Giving feedback on existing Tanks/Healers can still be valuable, since those revamps are probably very early in development or still very much subject to change.