Actually all the GTA released 'till today look like crap, they're fun to play basically because it's a huge sandbox to play with..that and the radio stations
The fact that they looked like crap doesn't mean they didn't do their (pathetic) best at trying to make it look good. Also, I remember reviews going on about "amazing graphics" and "great facial animations", in the face of overwhelming evidence.
Of course, there was the "sandbox" approach, meaning that in between missions you could do whatever you wanted, provided all you wanted was drive aimlessly while listening to the radio, and maybe shoot people. Yes, it was fun, but only for a little while, and after you've provoked the army to start hunting you and then stolen a tank for the third time in a row, the attraction palled somewhat. Still, it was a sort of fun way to pass some time. This, however, got you nowhere, because despite all the "nonlinearity" hype, the path of progress through the game was pretty much set in stone.
Okay, so we have a relatively fun sandbox in which to play aimlessly, and somewhere in the middle of it, and entirely unrelated with what we do in our "free time", an actual storyline with actual missions. And it was actually fun for the first couple of hours. The problem was that every other game only added a new storyline, and nothing else. "Sequel" hardly seems like an appropriate word when "expansion set" jumps so readily to mind. Everything is pretty much the same, but with a few extra missions. Unfortunately, all the fun ran out in the first game, and the only purpose of "sandbox", is having a break from missions, and the only thing you did was drive around and listen to the radio (the only part of the game that's actually new in every sequel), because stealing yet more tanks gets old really fast.
GTA 4? Case in point. What has changed since GTA 3? The resolution. It's HD now. Anything else? Not really. "GTA 4 is yet another GTA clone" sums it up pretty well. We've all played it before. All it has to offer now is better visuals.
Now consider a Wii version. It couldn't have sparkly shiny new graphics. Not that the Wii is incapable of shiny pretty graphics, mind you, it's just that those require work. So, gloss is out, what are we left with? GTA 3. Um, been there. People are already complaining about having to pay again for games they paid for already on older consoles; I sincerely doubt they would be willing to pay again for GTA 3. They'd be better off playing the original on PS2. Okay, a Wii version could have some actual novel content, or Wiimote-specific controls, like the Godfather. Only... no, too much work again, for the measly profit derived from the few thousand Wii owners who would actually buy the game (because between people who would download it instead of buying and the typical/intended Wii owner, i.e. your mother
who wouldn't play it at all, several thousand is an optimistic estimate). Any possible Wii version would be some half-assed byproduct hammered together from old PS2 versions.
So, yeah. A new GTA on other consoles can offer good looks and not much else. A GTA on a Wii could offer... nothing much. Seen it. Old. No point. We've had all the fun that can be had in a sandbox, and all that's left now is the cat excrement.