I certainly feels like a buff. I hadn't played in a while and got back on the game a few days ago. I didn't even know the patch had happened, and jumped in a game with Samus. I was landing and walling with power missiles all day, to the point where I was able to control fights unlike I had been able to before. The fact that they travel faster means that the missiles is reaching them quicker, not only giving them less time to shield, but also means you can put out more missiles overall in a shorter amount of time. This also helps when mixing up between power missiles and homing missiles. For example, I like to alternate homing missiles into power missiles on the ground, so now that the PM is faster, they have less time to approach after avoiding, shielding, or getting hit by the HM, so you essentially have a much better pressure game. throwing in some uncharged neutral b's mix things up a bit more due to the speed difference between it and the missiles, so its much more difficult to get in on Samus now I think. I was also playing against some awesome players who had already been playing the game post-patch, so I felt pretty good about this change overall.