Personally, I'd say keep The Wave reservation. A friend and I visited Trader Sam's about 4 months after opening and needless to say the drinks are strong but the apps are really disappointing (on top of being expensive). We ordered the Portuguese Sausages which came with three sausages smaller than the tiny corn dogs they sell at the parks. The big kicker for us was that we were a party of two and we got three sausages. We ended up trying to cut the last sausage in half with the plastic shish kabob style stick that came with the app as we never actually received silverware. Everyone says the tacos are good, but I can't justify paying that price for three tacos that are 1/4 the size of a regular taco.
So all in all, unless your party is a VERY light eater or you have tons of cash to blow for no reason then yes, I'd recommend dinner at Trader Sam's. If not, keep the reservation at The Wave (or might I recommend a dinner at Trail's End. The best kept Disney dinning secret).
Anyway, hope this helps
Edit: Also, it just dawned on me that if you don't mind sitting in the outdoor area, you might be able to bring in food from Captain Cooks, which is a much better value for about the same price as the apps. But I'm not sure what the rules are regarding that.