I don't necessarily think so, I don't see how prime Mercer would have an easier time getting past that jab. Wlad is much better IMO at using his height than Lennox was who fought more athletically and especially against Mercer failed to really impose his size on Mercer, nor did Lennox tie Mercer up on the inside which Wlad would do everytime Mercer got in close.

I think Vitali would be competitive and probably at the top of any division all the way back. IMO it wasn't just Lennox's age that made the fight so hard for him. Vitali is that good. He's so tall, great chin, good defensive skills, and still pretty athletic. This guy could compete with anyone who's ever fought.