No…Jeff literally already adressed this in his post, and I agree wholeheartedly as a support player with everything he says about it:
Obviously solo tank played, performed, and felt much better to the majority of the team. The only support I can see solo healing is Mercy. She’d probably be a must pick in a solo healer, 3 DPS system.
They could just lock the tank role into Main(Shield) and off tanks and have one main and one off tank per team and keep 2-2-2 without having to worry about double shield or double main tank ever again.