Nintendo will have more third-party support this time around, but owning them? I doubt it.
There are a few of them that have chances to become million sellers, but they will be titles that are specifically designed for the Wii.
No matter how large the Wii's install base becomes, it won't ever see "the big stuff" like Metal Gear, Tekken, Devil May Cry, Rainbow Six, etc. The hardware isn't powerful enough and its online service is by far the least impressive of the three.
Ever since the N64, everyone has bought Nintendo's systems(handhelds included) for their first party titles and nothing else with multi-platform third-party titles selling more copies on other systems. That being said, it'll be interesting to see how third-party titles fair once Nintendo starts releasing more of its flagship titles like Super Smash Brothers Brawl, Paper Mario, Mario Galaxy, Mario Strikers Charged, Metroid Prime 3: Corruption, Kirby, Donkey Kong, Starfox, etc. Third-party titles such as Rayman, Red Steel, Monkey Ball, would have probably been largely ignored had more of Nintendo's first-party titles been available at launch.
Consoles owned: Saturn, Dreamcast, PS1, PS2, PSP, DS, PS3