I think they will. Amazon does listen to us as evidenced by some of the features they added or changed with the K4 line. Android definitely supports folders, and many of the 3rd party Android reader apps allow you to place your books into whatever folder(s) you like. A built in Collections feature would be better, but folders would work too.

Personally, I will do most of my reading on my E Ink Kindle. Collections are VERY important for my E Ink Kindle as that is where I plan to keep my library of eBooks. I will only load a few books at a time on the Fire--the ones I'm currently reading. I'm sure the lack of Collections for those who want to load hundreds of books on to their Fire will be a major issue though.