That's what it looks like...unless Nintendo surprises us at E3. Considering their track record the last few years on what they consider "hardcore" games these days, it seems unlikely that they will take the time to make a new Metroid, when they can rake in the cash with no effort with these remakes.
Now that I think of it, is Punch Out Wii really that different than the old Punch Out?? Most of the old characters are there with the exact same moves. The only thing that really makes it different is that it has multiplayer, just as the MP Trilogy will have multiplayer. But is that different enough to warrant another remake? Why not a completely new Metroid with multiplayer? At least put in an online mode, I mean they did it for the DS Metroid!