Hiro wasn't training to fight! He was training to detatch from his emotions so that when the time comes he will be mentally able to make the killing strike. He has no need for combat training - He can freeze time and space - as he often reminds us. He already had Sylar at his mercy once but he hesitated and lost focus. Had he been in that same encounter now I'm sure things would have played out very differently.
The only thing we know for sure is that Ted is not [any longer] the exploding man. Peter and Sylar both have the potential to destroy the city. I guess we'll know in 4 days [Approx].