Secrets to Lightning Fast Mobile Design

This, mostly brilliant, slide deck has been floating around the 'nets for a while.
It's from Mike Krieger, a co-founder of Instagram. He makes a lot of good points about mobile app design - not the visual, but the functional.
The only thing I disagree with him, is on slide 74. He's talking about uploading in the background, while the user is entering the meta data of a photo.

This is a brilliant feature, but sadly, the way they have implemented it makes the app stutter jump around in the transitions when it's uploading.
Even on a dual-core 4S.

So my take is: look for design optimisations like this, but don.t do it at the expense of the overall experience.