Fisrt of I would like to say I've been thinking the same thing. It would be the smarter decision. Plus, it would greatly help Cafe in the begining. 

your first point a) that wouldn't be too much of a problem seeing how the Dragon Quest games don't focus on realistic graphics anyways and more of a stylized "anime" sorts of graphics.

b) true, this would be the only thing that would worry SE. But I'm on the fence on this. On one side, there's that dreaded belief that Cafe will start off slow, and I mean SLOW. Then again SE can just say well this is Nintendo they know what they're doing and plus this game will jump start the Cafe a lot.

But at least we can agree on one thing, SE knows more about the Cafe then we do so whatever they do is for the best . . .

About a) i was mostly thinking on the resources needed to move to a new hardware and if possible or if possible using any feature on Cafe that would benefit the game

The last reason seems to be the strongest one as people mentioned, SE tends to release DQ games on the "winning" console.

But who knows really?

There`s one of two things that could happen: SE could release a Wii version and a Cafe version (with some improvements) on the same day (the day of Cafe`s release), like Nintendo did with Zelda or just release the Wii version on Cafe`s release day, giving the chance for those who have a Wii to play the game on it and those who will be buying a Nintendo console just to play the game, to offer them a choice of either purchasing a Wii or the new Cafe!

You know, SE has been recently confirming release of DQX for Wii every couple of months. But they haven't really revealed anything about the game other than its well into development. No, info, no screenshots. Seems kind of fishy to me. I think they're doing this so people (in Japan mostly) don't loose interest in the Wii. There is a very good chance they're doing this so they can finally make an announcement that its being moved to Cafe (likely at E3)

If i am remebering correctly all of the Wii games are built in HD and just downscalled to 480p so this shouldnt be an issue to release this on the new machine.

If i am remebering correctly all of the Wii games are built in HD and just downscalled to 480p so this shouldnt be an issue to release this on the new machine.

Yeah I keep hearing this but no one ever shows proof, I'm with theARTIST0017! Source!

DQ has historically gone to a console with a highe userbase and has recently released in the final years of a platforms life.  I don't see why S-E would suddenly make an exception with DQX and launch it on a new untested console which will have a miniscule userbase.