I'm not actually sure what the flat attack bonus means yet.. his spark bc buff is actually a little less than Deemo's, but deemo was overkill already most of the time, and his stats and damage more than make up for it I think. We'll see... either way Karl 6* is a long way for us anyway, it's just being announced for JP.He looks like a decent BC generator, but there are plenty of new units who do that but with better BB and SBB. I'm not sure what 100 flat attack bonus means, is that a 100% attack buff like Michele?
The buff portion sounds awesome, but it's self only. Good stats though.
Also they boosted a SHIT TON of older units, take a look at all of them in this thread if you want.
Update Notes (JP) - 13 November 2014 : bravefrontier