Adding simple sugars to raise OG and dry out the finish a bit is common when brewing IPAs. Some people say up to 20% is OK, but I never go over 10%. In an AIPA most people want the hops in the front seat, so a less malty profile is just fine. I like to avoid crystal malts and go with Munich or Vienna for color some maltiness for balance if needed.
Also, I doubt that you'd ever notice any difference if you replaced the dextrose with table sugar. Put the extra buck or 2 into more hops for some extra kick.