I had this reorganizing problem too, but still wanted to write on a notebook. I finally discovered Kokuyo campus smart binder. It's an A5 or B5 sized loose leaf binder that has these small plasic rings and can hold about 30 pages. Reorganizing is simply opening the binder and rearranging the pages and that worked really well for me.
I have this too and really loved it. But now I just use the cheapest B5 notebooks I can find, for the refill paper was somewhat expensive. For organization, I use the postit-like flags to label pages, and sometimes I'll write a table of contents on the front cover when the notebook is full.
I do the same for the same reason and have the same Kokuyo binder! Though recently transitioned to just an American size (?) loose leaf with binder paper for cost an ease of procuring paper, as well as that I find the Kokuyo cumbersome to put in and take out paper with so many holes.
