I'm a huge believer in the superiority of walkable cities (the single main reason I left the U.S since outside NYC they don't exist in the U.S), but superblocks aren't my favorite approach. To me it makes everywhere look the same and kind of boring. I prefer how they do it in Asian cities like Seoul and Tokyo where they just have a lot of pedestrian streets and multistory buildings. Virtually every major European city is walkable, and I find it significantly more interesting to walk through cities like London or Paris than the boring grid superblocks of Barcelona (though I still like Barcelona).