It could end up being the best version. That has happened with a few games on Wii U where the (late) ports actually did offer some meaningful improvements.
But the Wii U version receiving no DLC or extra content has (apparently) been confirmed via the Watch Dogs twitter account. We'll have to wait and see exactly how accurate that report is, but it's unfortunate if true.
That said, a lack of DLC doesn't typically hurt my interest in a game. It's pretty rare that I spring for paid DLC unless I really love a game, so having only the base campaign is usually enough for me.
What
does hurt is the fact that Watch Dogs on Wii U is releasing months late, presumably at full price, with no marketing push, and after getting middling reviews on all other platforms. Is it worth paying extra for the best version of a mediocre game?