In case you didn't notice the result of the last election, and the one before that, the Labour Party has already made itself unelectable. Whatever Corbyn might do, he certainly can't make the situation any worse - do these apologists for "New" Labour really think that, having been comprehensively shown the door by the electorate twice, more of the same is somehow going to magically work next time?
I'd have recommended original thinking to you, rather than merely parrotting the party line of others, only I fear that you'd find it impossible.