Some of the electric retracts have current limiting, in the event of a bind. The retract draw is only momentary and not continuous like the servos. I'm more along the school of thought that an ESC with a 3A switching BEC would probably handle the load, and that heat buildup is as much of an issue as momentary peak draw. The only BEC failure I ever had was almost certainly due to almost no air circulation at the ESC, and the weak 1.5A linear BEC finally shut down at the end of a long flight, driving 5 servos on 3s lipo. I believe the line voltage increase due to dropping throttle on landing approach is what finally shut it down. To each their own, but I wouldn't cringe at running a number of efficient 4.5gm servos and electric retracts on a 3A switching BEC.
I've heard of paralleling BECs with Schottky diodes, but I'm not sure how this really works in practice.
On Mark's thoughts, some folks have ran 4 engine planes with 2 engines and 2 props freewheeling. In the air nobody can tell the difference.