Leadership of a major political party brings with it the ugliness of party infighting, media attacks and everything else. It takes a good leader to deal with it all effectively (not by offering a once in a lifetime, country-ruining referendum, though) to sort it out. I don't think he's a strong leader. He's a principled guy, and no doubt he has many supporters - over 60% of members voted for him - but there is no doubt in my mind that he is, and has been, out of his depth.
Ultimately, however, the Labour party is left in an awful mess whatever the outcome. Corbyn goes and the majority of his supporters are left feeling let down (although I would be interested to see how many who voted for him would vote for him again), or he stays and has to win over a large amount of MP's who don't want him there.