The page number idea always struck me as a little silly. If a title comes out in paperback and hardback, which set of page numbers do you use? What if there's a revised edition, or a second printing? I'd much rather settle on a new method of recording location within an ebook than graft an (in the long run) unworkable old system onto new technology.
But I'd say the new touchscreen support is more important.
Speaking of updates, I somehow managed to miss the one from last November, when Amazon added dictionary support, a multi-column reading mode, and better library management. The new multi-column mode really makes the app a lot mroe usable.