I have a suggestion for a new game type, very similar to that suggested
here and another discussed
here.
I envision it basically as a special implementation of random battles, where there is a team building stage that consists of drafting Pokemon from randomly generated packs. The Pokemon would be generated the same way they are for RanBats, but would be created in packs that have specific distributions (For example, 1 OU tier, 2 BL/UU tier, 3 NU tier). There could perhaps be like a chance of an OU Pokemon being replaced with an Uber.
There are two different ways I think of it going (both of them inspired by Magic: The Gathering). There's sealed, wherein a player gets and opens all of his packs and builds his team from them, and draft, where each player picks one Pokemon from a pack and then passes the rest of the Pokemon to the next player to have one Pokemon picked, till the pack is exhausted and the next pack is used.
I came up with this idea in my Freshman year of college, I don't know if Pokemon Showdown was a thing yet. I threw together a little C program for generating a sealed pool of two packs and I later remade it into a little javascript thing and was going to write something just like Pokemon Showdown (and create a community around it), and then I lost interest. Now I'm must more experienced and I would be willing to completely write the mode myself, and the battling of Pokemon Showdown is already written!
If anyone is interested in the little web thing I made for generating sealed Pools of two packs, you can find it
here. Be warned, it's all stuff I did my freshman year when I didn't really know what I was doing. It's also all based on Gen IV since that was the last gen I ever cared about (and only because of HG/SS :P).