"Could you elaborate on that a little bit? I assume the tricky part you're referring to is juggling banking and holding attitude?"
Especially with a super critical wing. Aerodynamically you're not in a good place, but the engines and fuel flows love it. The aircraft becomes extremely twitchy. A high speed stall may not be far way if you mis-handle the pitch attitude. As BEagle pointed out earlier the sums actually leave you with quite a small gap between cruise mach no. and the stall. Have the thing at the max weight for the altitude and the margin is at its' thinnest. There was in an incident report some years ago about a Challenger 605 crew who climbed too early on a transatlantic flight and nearly lost the aircraft because they were overweight for the flight level they wanted.
Because auto-pilots are digital they are far better at controlling the aircraft at altitude than pilots. It is really interesting to watch a crew descend from FL420 to land without use of the automatics. The handling pilot will be mentally calculating at a hell of a rate while concentrating on flying as smoothly as possible, the monitoring pilot will be doing everything else, including the same mental calculations which the crew share between themselves, and doing everything else is quite a lot.
As an exercise it is one that makes for a sweaty shirt, there was a Greek airliner that decompressed a few years ago, a steward on a portable oxygen bottle got into the cockpit and took one of the seats (both pilots were unconscious) the steward held a ppl, if he had yelled for help on the radio the outcome may have been different, it is believed he disconnected the auto-pilot and lost control of the aircraft; The expectation of how a swept wing jet will fly compared to the reality catches people out. Down low, in the circuit they are great, you need to concentrate on inertia and the outside picture. At altitude they are utterly different, challenging and require different handling, and after nearly thirty years I'm still learning.
SND