Imagine it like this. I can do unlimited Reactions. I have Counterspell. 3 booyaghs in battle. They each cast a spell. I'm out of level 3 spells. No choice. They only cast Bless, but I wasted my level 3 spells on it because of unlimited Reactions.
To make it work, we'd need unlimited spell slots too, but then no one would EVER cast a spell again, for Counterspell could then stop every one every time because of unlimited Reactions and spell slots.
In fairness, I've already put forward my opinion that Counterspell shouldn't be a reaction.
In my opinion, it should be a readied action that burns up your action. Ready versus spell to counterspell. If someone begins a spell, they are interrupted, and it's now your turn to try your counterspell. If no one begins a spell then you wasted your turn keeping an eye out for one.
