SNES and N64 had it perfectly. For SNES, we received Super Mario World, Super Mario RPG: Legend of the Seven Stars, Mario Kart, and Super Mario World 2: Yoshi's Island. That's a GOAT lineup.
N64 had Super Mario 64, Mario Kart 64, and Paper Mario, with the seasonings being the first three Mario Party games.
Gamecube had it close with Paper Mario: The Thousand Year Door and Mario Kart: Double Dash (two of my favorites in their respective series), but Super Mario Sunshine fell short and the Gamecube Mario Party games were mediocre.
Wii had two great 3DMario platformers, a good Mario 2D platformer, one solid Mario platformer/RPG hybrid, and no good Mario Party games with (imo) an average Mario Kart. Not a winner, imo.
Wii U has Super Mario 3D World, New Super Mario Bros. U, and Mario Kart 8. Not even going to bother with the farce Mario Party game. Again, not a winner because it lacks the RPG.
In my opinion, the perfect lineup for Mario during a generation would be:
A great 3D Mario platformer
A great Mario Kart
and a great Mario RPG (whether Paper or Super Mario RPG style. No Mario and Luigi, pls)