I am a firm believer in bigger is better. Really the question your asking is how will the increased surface area on the water affect on your riding. Typically I notice two things when going in either direction, getting shorter the board feels more nimble and seems to transfer edges faster. I think that the right move for most is going bigger, while the board might not feel like is has the same snap when transferring edge to edge or slayishing the wake you going to notice a much more stable ride. For me and others I have taught lessons too, I notice more predicable pop and easier landings. You might not notice this as much as not only are you considering going up in size you considering a different board.
Hope this makes sense.