Evidently not ;)
Okay. Same sequence in the Supra - 3rd gear corner, so a 70mph one or so, right? Into corner, brake hard and late on trailing throttle, car is in 'power' mode, onto throttle, car has already kicked down into second as I touch the throttle, digs in, maximum torque and off I go. No superfluous change. Not only that, but no need to think about changing up; hold the throttle and I'm doing 120 without any diversion from steering and watching the horizon for hazards. Perhaps not a concern on the track, but on the road my entire attention is focussed on the road and the car's chassis - I'm awful company in a car ;)
Engine braking - switch overdrive off or use 3rd/2nd lockup depending on your gearbox. IIRC the Jaguars have the J-gate transmission which is designed /precisely/ to let you have some manual control over the gearbox.
Do not blame the tools until you're prepared to use them correctly and fully - this isn't a criticism per se, but you can't just dismiss autoboxes out of hand when you haven't used them. FWIW, I can't stand the XJ40, I find the chassis too indecisive a lot of the time.
Richard