I hear that, my 5R55E is doing fine also. I've just read and heard about the bad A4LD for years, and avoided the V6 trans. This is a descendant of the A4LD, so it shouldn't be pushed too far. I do hope the PCM tuning will firm it up a good bit, I still would like a more positive feel at shifts.
What fluid are you using BTW? I swapped messages with Amsoil recently, they have a racing version of fluid that is a type F non friction modified fluid. That means that it grips better, or the clutches grip better. The modern fluids all have lots of friction modifiers that are great for normal use, street use, smooth shifting etc. I don't know the details of how fluid changed since prior to these, say 1990. Amsoil suggested not mixing as I was thinking of with my supply of ATF. They said leave it all as their normal ATF, or make it all the racing fluid. They mentioned that it's for upgraded frictions, a trans made to take the harder shifts. Meaning that the racing fluid would hold better, but may be harsh to stock clutches or create chatter. I think I could use it with my high performance parts, but I didn't want to buy an additional 18 quarts plus have the 14 or so of regular ATF as spare.
I may try it some other time, but you might see what options you have for frictions to rebuild a 5R55E with.