If you're after animation then you typically are going also for a more powerful (and power-hungry CPU) aren't you?
Maybe I'm a semi-Luddite but seems to me that the key ingredients for mobile reading are three things: clarity, clarity, and clarity. After that long battery life and light weight. If you don't do a clear, readable display then the advantages over paper books are lost. Consider in my (older guy) definition of clarity that screen size matters, too: I can focus on my Clie to read something, but it's a pain with progressive lenses - thankfully I didn't get into the PDA habit too badly. Book-sized readers have book-sized display areas, couple that with high-resolution display and you've got me.