That might actually make it worse to be honest. If it made a target spell uncounterable, the spell could be countered again in response. That would make this land basically a super specialized, repeatable Counterspell.

Usually you know when you want a spell to resolve (wrath, commander, wincon, etc) so this lets you prepare for that. In brawl, I would expect this land to be a very strong land even.

The main issue I have with it is actually standard, where counterspells already suck, and paying 2 additional mana to prevent something that’s already unlikely will be way too slow for most decks to actually compete. Maybe some mill deck might play a copy for mirror matches to resolve Jace or something. Otherwise, Cavern of Souls does this for free in a lot of decks. If/when that rotates out, this might see some real play.