There is an issue with the loss of control utility when you can herd through taunt and AoE the herd, but that's not just a CoH issue. The bigger problem is that while one tank/brute can hold the AV's aggro, you need multiple holds to keep them in place. This is where break bars can help make control really shine.
As far as support, my blaster will appreciate any she gets. And the value of support shines again when you get to incarnate content.
If you're nerfing to make them 'relevant', then, yeah, you're making them mandatory. Metas are a thing.