So many people underestimate how hard it is to defend against multiple attacks simultaneously?
When Thanos drops his shields (in which he will because of character and because he wouldn't be able to attack directly with them up) then I have a hard time seeing him defending against Mjolnir coming at him while the others throwing attacks at him at the same time. If a good attack lands then he will be stunned and the others would just capitalize and phuck him up.