At first I liked the idea...but now that I consider it, I think maybe they might be making a mistake.  If you have 2 big blocks a year, that is gonna stretch the financial base of the consumer who likes to keep up with Type 2.  A large block takes considerably more money to obtain the cards in it that you want.  A smaller block is a whole lot less expensive to obtain the playsets.  As for Pre-Releases, it may actually bolster them by having 2 big sets, initially, however, the second one (Jelly) may have a sligtly smaller attendence.  Not sure on that one.  
Overall, I think that maybe we will have to wait and see how the community at large will react to all of this.  They may actually surprise us.