Super Mario Boards

I tried designing models on blender and I failed miserably.

I use Maya to design models, typically. I've heard that Blender has a pretty good sculpt tool, though.

I would love to see a Baby Luigi skin in Overwatch

Agreed.

It's probably not going to happen, unless Overwatch has a quick and easy system to do a proportion trick that'll have a character be his size (like in L4D or GTA V) but even then, Overwatch has a gutted single-player/local multiplayer modes that I don't really like.

Can you put him in Doom?

I mean I could, but considering it's an FPS, all I need to make his his...face sprite? Maybe guns too. But the game's spriting looks pretty complex, they're prerendered models most likely.