May has proved useless, but one suspects she was handed an impossible task; to get a deal with an unwilling EU and then find it was acceptable to both the Leavers and Remainers (not that the Remainer MPs should still be trying to remain, but politicians seem to be an immoral lot, no matter what they claim they went into politics for). Foolishly she ended up trying to please both those supporting democracy and those against it, and her agreement with the EU "fell between 2 stools", and was predictably liked by no one.
However Corbyn likes to hint he's for leaving, whilst leading a party that is clearly for remaining; and is demanding that since there is no possibility of a decent deal, he wants no-deal removed as the option as well. Pushing for this "limbo" indicates he is hoping to run into a withdrawal od Brexit or a second referendum in the hope of stopping it then, or possibly the unachievable hope of continuous procrastination. So clearly he would be many times worse when it comes to Brexit issues, than May has proved to be.
Regardless what one thinks of them and their parties for other matters, Brexit is the one off major issue now and needs to be the priority since one may not get another chance at getting it as right as possible. This means the Tories have to stay in power, and the MPs have to understand that this is a democracy and they have to deliver that which has been demanded, not try to persuade us to allow them not to. Leave means "leave", not "leave if we have a nice enough deal, otherwise not", nor "leave in name only so we don't have a say but still get dictated to by a foreign power group".