I'm clearly in the minority here, but I didn't particularly like the arrival of Stardust. In fact, I found it a little silly and over the top. When the character of Golddust debuted, it was a different era, when over the top characters were a little more prevalent. Golddust, despite his family history (and to some degree, his personal history), was pretty much an unknown entity, so it was a new, unique gimmick assigned to a relative unknown, in an era when cartoonish guys were more frequently seen.
In this case, it's a guy who everyone knows, who all of a sudden, for dubious reasons, has decided to paint his face, don an unusual costume, and try to recapture lightning in a bottle (in a manner similar to the transformation of Jeff Hardy into Willow). At best, this will go on for a while, with the brothers enjoying some success in the tag team division (which is hardly an enormous accomplishment in today's WWE), but this will ultimately culminate in one brother turning on the other in the tired and true sibling rivalry. At worst, this has the potential to turn Cody Rhodes into a joke, someone who may be difficult to take seriously in the future. Guys such as Brodus Clay, Fandango, or Santino Marella have gimmicks that can attest to the fact that it is difficult to go from unusual, non-mainstream gimmick, back to a serious character. I guess when push comes to shove, nothing ventured, nothing gained, as I don't see Cody Rhodes progressing beyond the upper mid card anyway. It's just that I would think it would be a shame to see Cody Rhodes deteriorate into a comedy gimmick who no one will take seriously ever again. Kind of like his former tag team partner.