RE: upgrading to ailerons
As to the DS being overpowered from what you see in the video, I can't say. It is indicated that the plane was flown with the throws set to high, so the controls are set for advanced flying. It's also available with a GWS 100 motor. You may want to send them an e-mail an ask about it.
For myself, I like the idea that it's a full 3-axis control plane that I can grow into and do more things rather than use it as a trainer and have to get a new plane when I've hit its limits.
Cheers!
BobbyG