There are plenty of good options for RVD. Axel, Ambrose, Wade Barrett and Fandango are the best in my opinion. RVD is immensely popular and the WWE should use that to get easy heat for their heels. Moreover, as he has proven, he can work some fantastic matches.
A feud for the Intercontinental Championship, a belt RVD has won numerous times, could be interesting. RVD could be the next person to help Axel get over. I'm not sure how the Paul Heyman situation would play out. Him turning on RVD and Punk at the same time might be overkill but the possibility of RVD and Punk v Lesnar and Axel is something I could get excited by.
RVD v Ambrose could be a classic. I have my worries that The Shield could get stale very quickly and Ambrose feuding with RVD would keep them fresh. RVD is incredibly over so it would ensure The Shield remain hated.
Barrett is desperately in need of a program. He is far too talented to be left of PPV's and without direction. RVD and Barrett could be a good match and, like the other options, it would give him easy heat and ensure he has momentum. The same idea for Fandango and a match between him and RVD could be a show-stealer.
Personally, I think all four options could work but my favourite is Ambrose. Matches between the two would be of a very high quality and would keep both relevant. Moreover, it would help the US title.