Absolutely.
I think a DPS who never pops a defensive cooldown, an oGCD free heal such as second wind or bloodbath, or never uses party aiding buffs such as mantra and eye for an eye to be just as bland as the healer who refuses to dps and the tank who feels his job is exclusively to hold agro.
But as is very prevalent in this game, a lot of things the DPS classes do are hidden in a protected veil, while the tank and healer classes are more open to criticism, so generally, nobody sees or cares that most DPS don't use 2/3 of their abilities.