Mearls here says something like "It turns out needing two islands to cast a counterspell is a part of why it works," so, yeah, he definitely has learned that the preparation cost matters.
Having 2 U to cast it meant you had to really dedicate to blue to do it early.
I still think D&D could benefit from having lower cost counter spells that only work in specific situations like versus certain schools of magic or versus certain monster types.While it's a different vibe in D&D than it is in M:TG, I think "stop having fun" effects are ultimately kind of toxic in play because of how they really mess with the joy of your fellow players. Less toxic maybe in D&D where the PCs win most of the time anyway and you're really just figuring out how they get to that victory. But still, clearly...impactful...
Countering conjuration spells or fire spells might just impactful enough to mater but not universal enough to annoy.
Control never left when I still played.The death of Counterspell in MtG is a myth.
Blue based Control/Counter magic is a part of nearly every format, and certainly every good and healthy meta.
But Draw Go MUC took a hit in the less older formats back when I still played.