RE: Phasing out 72 Mhz.
There's absolutely nothing wrong with 72 mhz systems. They are very reliable and I've heard nothing of that frequency being banned. More and more people are going to 2.4, as I have, but I do still own and operate a 72 mhz sytem. The cool thing about 72 mhz is that since hardly anyone as using it anymore, it's much less likely anyone else will be needing the same channel as you. As for 2.4 not being reliable, I've not had one single issue since I purchased mine. I have the Hitec Aurora 9 and absolutely love it. So, if you ever decide to go 2.4, this radio (and it's receivers) is the most affordable out there. It's also the most user friendly I've seen.
The only down side to 72 mhz is the fact that many events are 2.4 only now. The reason they've gone this route is to eliminate the possibility of same-channel interference. So, if there's no problems at your flying site with 72 mhz, and you don't plan on attending any large events, there's absolutely nothing wrong with staying with your current system.