We're still in infancy on small and touch screen devices and we don't have a ton of reliable data as things are still changing too fast.
It's something to keep in mind but does anything have any alternatives when you have more than 5 items?
We'll settle over something good enough for most cases, but it'll not be the sandwich alone, and I'm quite sure we'll stop using it at desktops on due time. Also, we'll probably need to rethink some APIs for getting a real option.
This way my two most important pages get heavy traffic without removing the ability to access the other pages which get used less often.
Hamburger icons are great for large numbers of pages no one uses particularly often, but are necessary for the app to work (Settings, Profile, etc.) and as a fail safe to always be able to navigate to where you want. The way to access you main pages should be baked into them (links, buttons, action bars) on the page itself.
The hamburger is just a cop-out so you don't have to think very hard about your app design.