Not yet, I am going to make sure I have money for a valve body IMMEDIATELY after the fluid switch. The old myth about not changing fluid on a high mileage vehicle has popped up many times, and it usually has something to do with freed up junk and the valve body.
I figure might as well drop in a good valve body anyways, not to mention the fact I should be assured a new one would be relatively clean preventing those so called failures.
I do not think I would go straight hy gard as it allegedly shifts pretty hard.
Contrary to popular belief, the switch to ATF-4 was a driveability issue (tcc shudder and "too firm" shifts) and to consolidate lube selections. (only carrying one universal fluid is much easier on the logistics end)
I will continue to keep some ATF 4 in the system, which has friction modifiers to smooth the shifts slightly and dye the fluid red.
My results wouldn't be a fair representation though, because a rebuild is going to be needed soon enough anyways.
The one concern is the fluids slightly higher viscosity verses the dacron filter. This could cause cold start buzzing and humming in colder weather. I don't think a different courser filter media is available for us, such as the ford guys who can swap to brass screens. Courser filter media seems counter productive, but with the conversion to external filter, it is a moot point IMHO