The biggest difference between the Wii and the PS1 or PS2, hell the biggest difference between this gen and other gens is that 3rd party were sure the Wii would fail and had little support at first whereas 3rd party corectly bet that the Ps2 would repeat the success of the PS1 and during the PS1 era they bet on it because they were pissed of with Nintendo's strongarm tactics (with good cause too) and sega's confusing hardware strategy.
This is the main reason why the Wii had such poor hardcore support in its first year (as they take longer to make than casual games) and why PS360 have a good chance to do better than GC/Xbox did last gen.
As the harcore games coming out on the Wii in 08 will have had more time to mature they should have a better quality and thus better sales (Nintendo doesn't sell more games because their is Nintendo marked on it, they sell more games because their average quality is much better with relatively few duds).
And once hardcore games have proven that they can sell on the Wii if the quality is there you will start to see more PS3/X360/Wii cross-platform games and eventually they will be developed with the Wii in mind first and then ported to the PS360 just like last gen games were mostly made with the PS2 in mind first (Splinter Cell is at least one exception to that though).
If you think that the Wii's lower power will prevent developers from targeting it first let me remind you of all the early 360 games that saw PS2 releases despite the even bigger power difference between PS2 and 360 because developers and publisher just couldn't ignore the PS2 behemoth. The Wii is not there yet, and you could argue it will never be but it is on the path to be there and we will have to wait until it is not sold out in all 3 major regions to know if it will fall of that path (depending on where the sales stabilise once it is not sold out anymore).
"I do not suffer from insanity, I enjoy every minute of it"
