In truth, I had begun planning for a revised edition of the AD&D game beginning around 1983. I made notes for what I planned, and those remained with TSR when I left the company at the end of 1985.
The UA compilation contained the initial pass at some to the revisions and expansions I envisioned for the game, but I had not had time to sit down and concentrate on exactly how I would complete a revision and what it would entail.
No matter, as that is now all water under the bridge for more than two decades now, eh?
Cheerio,
Gary