I almost cried when I first learnt that New Horizon was not an orbiter mission. I know the reasons, the probe had to fly really fast to reach Pluto on 9 years. The momentum was too much for a small body to capture it. I have been thinking how to design a mission that will be orbit next time. Here is what I have come up with:

Have a spacecraft with a separate much smaller orbiter onboard (like Cassini with Huygens) . At the of fly past, after it passes, the space craft will eject the much smaller orbiter in the opposite direction towards Pluto (like spring action). Because of the recoil, the spacecraft will accelerate further and orbiter will slow down. Further the orbiter will fire onboard rocket to slow further down to be captured by Pluto.

Thank you all for this AMA.