Pretty much exactly that, Mario Maniac. Nintendo first had the Mario Land series as their GameBoy Mario outlet. But, when they made Super Mario Land 3, they decided to pull an unexpected twist: put WARIO as the main character! It was such an interesting change, playing as the greedy anti-hero, that rather than make Super Mario Land 4, they kind of morphed it into a Warioland series, and hence Warioland II came out. Then 3, and now 4. One COULD say that Warioland 4 is really Super Mario Land 6, but I think that is an incorrect statement. The Mario Land series spun-off into the Warioland series, and the only shared title in SML3:WL.
Do I think we'll ever see another Mario Land? Perhaps, but doubtful. Wario is now the GameBoy "Mario" outlet, while Mario himself, with Luigi, still rule the home console department.
--Roy Koopa
--Oldest and coolest of the Seven Koopa Kids!
"What? You don''t think I''m the oldest? Come here and say that!!"