Brawl getting delayed until February is so totally worth it now. Out of all the new things Brawl was going to offer, never did I once expect a Stage Builder. You can make the stage as big as you want, add whatever background pattern, what music will play, and add whatever you want into the stage itself. You can try out the stage to see how it will feel on the fly too. You can make as many stages as you like too since it all gets saved onto the SD card.
Not only that, but you can also send stages to your friends. You can send your stages to Nintendo too and they've made a system where Nintendo will send you one stage a day automatically if you want. The stage you receive however will be replaced with another stage the next day oddly enough.
This is easily one of the biggest piece of news to come out of the DOJO.