IB had level 6 with Misaki, only because she had a constant source of energy. Touma would touch her, but she would immediately recover. Yes, and level 6 Misaka is quite strong. Touma had to summon 8 dragons to win, and even one angel dragon could devour black holes capable of destroying the entire solar system.
Yeah no... no...
No.
Last time we figured on that, she was at Island level, no more or less. And secondly, I'm virtually sure the Dragons get stronger with each one lost, they don't explicitly are all at maximum strength from the word go, that's kinda their main thing.
And IB has no problem with basic Accelerator, it was Touma who had a problem with it. And anyway, IB is in its incomplete state, I wonder if IB works at least 50% of its power. Only thanks to the fact that Touma is a combat genius (it was talked about in 1 OT), Touma was able to master IB at a very high level in a few months, Touma is actually very strong, but because he thinks he is a loser and bad person he often says that he will lose to an ordinary mage, although it is not true.
He DOES lose to ordinary people, quite alot actually. He legit got his ass kicked by a normal group of Navy SEALS/Green Beret. The dude consistently ends up at the hospital due to the injuries he receive consistently during fights.
So yeah, I don't buy him suddenly being this super strong man from nothing and IB somehow gets stronger based on the people he fights. Especially when that keeps popping up.