PlayStation Plus is a great service, especially for somebody like me who rarely has chance to play games and so would miss out on PSN titles completely if they weren't available as part of that service. But there are still issues that people have: not enough games, repeated games, not enough save space, no Vita support. If the rumour of an upgraded PS+ turns out to be true, some of those issues may be fixed.
Eurogamer are reporting that a large portion of the Sony conference on Monday will be dedicated to the reveal and explanation of an extended plus service. They don't go into detail on what it could actually be, but they do cite a Sony survey from a few months back which hinted at more games for a higher price. They also imply that there could be a new-look PlayStation Store and a plus-specific area for the Vita.
Will any of this come true? I guess we'll find out on Monday (the conference starts at 1AM on the 5th, for Europeans who want to watch).