Super Mario RPG 2. Bring back the cast, bring back the Smithy Gang with a new leader, bring back Geno and Mallow and Bowser and Peach, add Toad and Luigi and Yoshi and 2 more new characters for a proper RPG style cast (with the ability to swap characters out like in FFX).
That's all
Oh, and Super Mario Galaxy 2. Another GOOD yoshi's Island, and another GOOD 2D Platformer. Mario has only had 3 great 2D platformers (3, World, and NSMB U...yeah I know I'm weird for thinking that...it's the world maps)
My Console Library:
PS5, Switch, XSX
PS4, PS3, PS2, PS1, WiiU, Wii, GCN, N64 SNES, XBO, 360
3DS, DS, GBA, Vita, PSP, Android