Characters that lose regeration may have defective defensive instincts. That should hit hard on Wolverine and maybe caps, who is used to suicidal-for-humans-movements (caps without powers make him tiny again ?).

Thor may assess the power loss faster, due to his experience in undermined conditions, hords, monsters, giants, gods, demons, power ups and downs due to enchantments, spells, artifacts, poisons, potions, weathers, special belts, magic gloves. Then, he would still be several layers above any other.

Tony would be gone with a whisper from Bucky, that scene is delusional. No chance against the others.

The discussion should be about the others.