What would it be. I would want secret bases to come back. It could also make a really cool thing for Street Pass, like if you pass someone, there secret base could then be found in your game and you could battle them with the current party they had when you passed them, and you could even order items hat are in there base for your own base. Kinda similar to the Animal Crossing Street Pass.
Yes, I loved secret bases! Add some more customization capability, and you can have your own home away from home. This could work together with more returning features. Imagine the ability to take pictures with your Pokemon at different locations in the game, then turn the photo into a poster and hang it in your base.
I'm not a GRRL gamer; I'm just another kid who had a Nintendo and never grew out of it.