Christopher Low wrote on Feb 19^th, 2013 at 4:18pm:

It's the way that the plane loses altitude when banking at even relatively shallow angles that annoys me. Does anyone have a fix for that, or is it actually realistic?

With the autopilot? If you are hand flying, without pulling back on the yoke
in a turn the aircraft will descend. Wings that are not level will lose lift. Gravity is the LAW.