i've always thought that most superstars should have an impact finisher and a submission finisher. even if they are mostly known for one more than the other, i just think it makes them more multi-dimensional. also makes them more dangerous if one of their finishing maneuvers can come out of nowhere, whether that's the impact finisher or the submission maneuver.
as for Del Rio, i don't think he should have the double arm ddt. i know he's not an active wrestler on any active roster, but that's Foley's finisher. also, isn't it Drew McIntyre's finisher? i think so. if it is, then i say no because everyone should have their own finisher that is unique to them. also, i agree with whoever said that the powerbomb is best suited for bigger guys.
if he were to get an impact finisher, i'd suggest something more than just the shining wizard or drive by kick. maybe something like Mr. Anderson's Mic Check. only Del Rio could really emphasize that it's a single arm ddt, something that works the arm that much more. so it could be an impact finisher on its own or it could be a set up for his armbreaker submission.