Why can't we have a dancer class? And why can't we expand on the bard?

[Gardes]

Dancer would be nice as a healer because they'll be frontline healers which is something different; however, I do see some problems with a dancer healer because many AOE attacks like in garuda extreme do target healers so they might be very dangerous to use in certain battles

I think you're forgetting Ifrit EX. I love XI's version of dancer (dual wielding daggers, heal dances are instant but have cooldown and cost TP instead, has a combo point mechanic like wrath that lets then convert it back to TP or other effects) but imagining that kind of healing dancer in ifrit ex, well, I can't imagine it going well. Now that I think about it, there's T7 too? I'm sure there's more. The idea of a melee healer in this game is starting to sound implausible...

Throwing daggers maybe? I don't think a 25 yalm long whip is a usable weapon.