I can't promise I won't play with a similar style in the future... look at them run, haha...
they are literally too cute. they looks even more cute walking :P You are right, Concept is really an important thing and it's very hard to think about a new concept and work on it.
Yeah, I think honestly that getting good at creating new concepts is something that takes a lot of practice. You basically have to become competent with an art style first, usually from doing lots of copying, which helps you train to get down what's in your head onto the page/screen, and then you can start to create characters and scenarios.
Hopefully though that process is somewhat enjoyable... because it does take a lot of time.