If It's Fun Keep At It

I personally do the same thing with many games I play, not just SC2.  The idea is actually a more focused version of what the Funday Mondays are trying to accomplish.  Keeping in that spirit of things, if you become bored with the box they've put you in remember that you can always go off the beaten path and come up with your own box.  

And seriously man, if it's making the game fun for you and making you better what more could you ask for?  

I might go for a more traditional path in my case, but something like that would be fun for the experimentation day.  (When I'm practicing, I come up with something crazy once a week and try it out to see if I can learn something new.)