Hunt and Gauthier are completely different players that fill completely different roles. The Islanders don't sub in Wahlstrom for Martin or Clutterbuck. They sub in Johnston for one of those guys and sub in Wahlstrom for anyone in the top-9. That's Gauthier's role for now, subbing in to the top-9 at RW, which then moves someone like Goodrow, Kreider or Blais over to LW if needed depending on who he is filling in for.
You are overselling Gaut big time. He really is nothing more than a 4th liner. He has no brain for the game