I'm amazed by the sophistication of iPad musical app development, it's like those developers just picked up the ideas and ran with it. The musical apps are elegantly controlling complex apps like Reason, Ableton Live, Logic Pro and even DJ mixing machines. I've seen the "video editing iPad apps" lists floating around, but sophistication of the apps just doesn't compare. I just gotta wonder why we aren't seeing the same level of creativity applied to video editing?

New movements in iPad MIDI: PolyChord, FL Studio Mobile, TouchAble, Livid Block, Alesis iO | Dubspot Blog (http://blog.dubspot.com/new-movements-in-ios-production-polychord-fl-studio-mobile-touchable-livid-block-alesis-io/)

I suspect we will begin to see more effort put forth in that regard, especially in view of some of the huge advances in video technology making high quality video much more mainstream. However, there is a significant stumbling block with the ipad; lack of processing power.
Serious editing needs a lot of horsepower under the hood, and unfortunately, the ipad ( and all other tablets currently available for that matter) are chugging along on the equivalent of a 4 cylinder engine.
I expect that there will be hefty boosts in processing power in the not too distant future...when you think back as little as five years ago, the sort of processing power that I have on my laptop today was hard to obtain on a high end desktop...until then, though I suspect we'll have to suffer with the reality that most of the apps are going to be pretty minimal in terms of real editing ability.

Wayne is entirely correct.

Video data streams are MUCH more complex and MUCH larger than audio data streams.
And while working with multiple audio tracks is workable on a limited processing power pad computer form - trying to do the same with multiple video tracks chokes things up in a hurry.

Essentially, the processing horsepower required to handle audio streams is not in the same ballpark as what is required to do video mixing.

Simple as that.