Using &pp= in the URL should allow you to specify how many show up per page -- it does for me. I'm not sure what it maxes out at, but it certainly should be more than 50. I put &pp=5000 in the URL and it showed all 78 subscriptions on the one page for me. Hold on..
To disable it, you just need to go into your user cp's options section and turn off the notification option.. should be obvious enough once you go in there. I'm assuming when the data transferred it just set all new users to subscribe automatically, which is a pain. Here's a cue to disable it if you don't want it, guys.