Kinda agree, but also disagree ;
Sure, without tanks, RBGs will likely be much easier to form groups, if that’s the case that 10vs10 bracket no longer allows tanks, then fair games. Games will be easier to host and strategies will change.
However tanks are known for being great defenders for specific strategic points such as Nodes, and in EBG’s cases, towers/bunkers.
In the case of blitz, some people enjoy playing niche ways like how Blood DK can make life difficult for healers or guardian can occupy a neutral node for minutes if played properly, in the case of Solo Shuffle / Arenas tanks can create terrible games in the lobbies, so indeed, a grey area indeed.