Splatoon is easily one of the best games to come out of this years E3, it was a surprise from Nintendo and none of us expected it, it was bright, it was colourful, it was Nintendo's version of a third person shooter but it shared Nintendo's passion for fun and enjoyment, with Nintendo's trademark style. Little did we know Splatoon was potentially going to be a very different game to what we know it as. This is because at one point Nintendo was "discussing the possibility" of featuring Mario as the player character. This is according to Shigeru Miyamoto who revealed this information to Edge. This is what Miyamoto had to say:

“There were heated debates over who the main player character should be. Whether it should be Mario, or a squid. When we talked about the possibility of it being Mario, of course we could think of the advantages: anybody would be willing to touch it as soon as we announced that we had the new Mario game. But at the same time, we had some worries. If it were Mario, we wouldn’t be able to create any new IP.”

I think this was a much better move for Nintendo in making the game original and brand new and I don't think the game would be as interesting if Nintendo,had chose to use Mario, the squid idea was far more original and interesting. Also it is what really drew Nintendo's interest with this years E3 because the game was interesting and a surprise. It was always good to see Nintendo bring new ideas.