No way. I saw it in 3D originally, and I loved it. The graphics were amazing, and although the film itself was pretty average, the writing, cinematography and characterisation were all done at least fairly well (and this is from a film-maker's perspective, too). As I say, the thing that made it good mostly was simply the visuals, though.
But I refuse to pay extra money to see it again if there aren't massive changes and whatnot. Why should I pay extra for 15 minutes more footage, that will be on the DVD anyway? It was good enough that I may at least consider getting the DVD at some point. So I'll probably see the extra footage then, or possibly on Youtube at some point (as it will inevitably be posted there sooner or later). 15 minutes extra footage might be good, but it's not worth another £5-£10 on my end.