TBH those who I knew, who knew him well, described him as a bit of a windbag!
Yes, Kinnock took the fight to and did grapple with Hatton and others on the extreme left and did he help clear a path for New Labour and for that he was given credit. However, as the then leader he missed the chance of ousting the infighting Tories after the downfall of Maggie and that was partly down to his tendency for extended oratory. John Smith/Tony Blair's path could have been made smoother and come more quickly if Kinnock had 'carpe diem' ... just an opinion!