We could have a friendly bet on that Welshie.
If Corbin is weak in any way, it would be because as the Labour Party is the biggest political party in Europe, it is indeed a very broad church, ranging from Blairites to Socialists, which he tries very hard to balance. His other possible weakness is that he is a very honest man, particularly about democratic processes, which has become quite a rarity in modern politics.
Oh and before you say it, the labour party has a strong history of rooting out Marxist entryism, but of course, you would know that, given you used to attend meetings with your dad.
Like you, I left the Labour Party. In my case because of Blair. I blame him for the current violent swing to the right of the Tory party. When Blair went to the centre right, the Tories moved equidistantly rightward as well.
Imagine chucking out of the party people like Ken Clarke, a man with a long history of honest political endeavour. Never liked his politics, but respected his integrity, unlike the chancers currently in cabinet.