Fair enough Moon. I got a different impression when I read your previous posts, but if you think he is clearly the best GM in the last 20 years and probably longer, I'm good with that.
IMO, Theo was being very gracious with most of the stuff that he said in the interviews after leaving. He was not going to blame Lucchino for everything that turned bad. He took responsibility for it, though IMO, the blame does lie with Lucchino.
Theo has been very clear with his team building philosophy. Theo and Lucchino have clearly butted heads many times. Many of the moves that turned out badly were due to the heavy hand of Lucchino wanting to make a splashy move. Maybe Theo allowed to get himself caught up with it, but I very much doubt those moves would have happened if Lucchino were not around.
To answer your question, the 'quality or work' probably was not quite as strong in the latter years as it was in the earlier years, but I wouldn't call it a significant difference. Again, I think Lucchino is largely responsible for that, which is why Theo wanted to leave.