This is quite an interesting one. I personally see three consequences: 1. Holyfield unifies the division, and is perhaps regarded as a top 3 all time heavyweight. 2. You then have a shuffling of the pack with the lineal title, like in the early 30s. 3. The Klitschkos grab the title earlier.
Without Lennox Lewis, Bowe would have held onto the undisputed championship in 92 so who knows what would have happened with Bowe losing the rematch to Holyfield and Holyfield losing to Moorer.
