I'm not convinced Counterspell is a fun spell to begin with. I mean..instead of two casters doing something, both do nothing with those spell slots, and slots just get drained. Spell Mantle vs. Dispel Magic is a much more fun active mage vs mage thing.
You speak for yourself here I'm afraid. I for one quite enjoy the feeling of negating an enemies attack. And negating an attack very much is doing something. A potentially very important something depending on the tide of battle. Also if by Spell Mantle you mean "mantle of spell resistance" then that is far more like "doing nothing." Passively wearing an item that improves your chancesto stop a spell vs actually making the decision yourself to stop an enemy spell.
