This wouldn't fix anything. People would ask for [Heroic: Gul'dan] instead. Lol.
However, moving past that, there's two types of groups progress groups and clear groups.
If you are a guy that's run Gul'dan heroic 500 times, do you really wanna bring 10 people that have never done it and could slow you down? No.
If you are a guy that's NOT killed Gul'dan heroic, then make your own group and progress it, or do you want a smooth run too (aka. kill it with people that already know what they're doing?) that's looking to be carried.