well i was doing good on this 365 for a while. a lot of things came up. making a game room downstairs, ordering new postcards, and getting my d300s snd lenses. heres a shot i did with 85mm afs and sb700 off camera.
That explains the flatness. With HDR you want very overexposed and very underexposed so that you can have the full range of tonality. By using flash you eliminated the "underexposed". Try your same shot with a lamp (continuous lighting) behind the rose instead of a flash and shoot your 5 shots. That should give you a nice, rich result in HDR.
I'm thinking the original prime shots are way better than these...seems like maybe if there were more colors in the subject it (HDR) would work better maybe???