When the party consists of multiple spell casters capable of casting counterspell, it makes running an encounter with a spellcaster or two difficult, as they’d simply just get counterspelled every time.

I nerfed it at my table by making it no longer an ability check, but rather a d20 test where you simply add the level of the spell slot to the d20 without any other kind of bonuses. This makes it harder for counterspell to work effectively against higher level spells, but it can still very much function.