Nutation
Explorer
This. So much this. Counterspell is amazingly powerful RAW; no need to give the players free information to make it even more of a sure thing. As is, bards (with magical secrets), and abjurers don't really have to worry about upcasting it much at all due to the bonus they get on the check anyway. The spell is meant to have some level of risk associated with it, no need to eliminate that entirely.
A very good point. I have been declaring spell slot level (this is in Adventurer's League). But, AL tables can have as many as 4 casters with Counterspell vs. one poor enemy caster. I should pull back on the info and make it more uncertain.