I think what really needs to happen is that more classes need utility. Whether it's one of the melee dps getting enough mitigation to become an off tank in add situations (not strong enough to handle tanking bosses though) or the bard getting some better utility songs that don't translate to just 'more dps' or 'sustain' (It'd be great to have a long cooldown that basically casts a party-wide shield. Kinda like having a second layer of Succor.) or so on.

If more classes brought specific kinds of utility in addition to their primary role (as opposed to just healers and caster dps getting literally all of it and bards just being passive buffs in the background), there will be situations where that utility can come in handy and more varied comps will be encouraged. Otherwise, that class can still bring their primary role.