Let's see...
3DS has already gotten SM3DL, MK7, Mario Tennis, NSMB2, Paper Mario, Luigi's Mansion, Mvs.DK, M&L, Mario Party, and soon Mario Golf and Dr. Mario or Dr. Luigi...
Am I missing any???
Wii U has NSMBU, NSLU, SM3DW, and soon MK8...
I assume Paper Mario U will happen, but somehow I don't think that will be the next Mario announcement...
I wonder if we won't get another announcement similar to NSLU...
Other than that, I'll wager Mario Party U...
Have a nice day...