Disadvantage is better than -2 the great majority of the time, especially if a nat 20 is still an automatic hit.It's actually IMO an upgrade over the old Protection Style (which imposed disadvantage) because it's completely reliable and so can effectively give multiple allies +2AC across multiple attacks; it only needs to be triggered once.
and how are you getting across multiple attacks?
across multiple rounds, yes. But never more then once in a round. And costing a reaction is huge.
Of course Protection Style was always bad.
That's the prevailing thought. They could have improved instead of nerfed it even further.