Perhaps I've been to above-average PDCs and below-par TechEds, but I don't think that TechEd is the PDC Without A Grand Unveiling that I dreamt of. I think that TechEd is essentially a goal-oriented show, a show where one goes to be educated about a technology with which one probably already works (for instance, "We're having DB performance problems, I will go and attend sessions about DB performance"). I think that PDC is essentially a vision-oriented show, to see things outside one's current toolset. I think that people fill gaps at TechEd and expand their horizons at PDC.
I feel talked at at the TechEds, I feel talked to at the PDCs. To me, a "Conference" is a different promise than a "Ed[ucation]."
So, when I talk of a PDC Without Announcements, what I'm suggesting is that if the PDC is where Microsoft hopes to capture the imaginations of the best developers, they would do well to have a conversation at the more ... I hate to say 'elite' but I can't think of a good alternative ... levels (for instance, Harry Pierson in conversation with David Ing would be a fantastic session).
For me, when the PDC was cancelled I did not consider replacing it with TechEd. Instead, I thought "Well, that makes OOPSLA 100%." If you've been to OOPSLA, you know that it's (a) a place where one's imagination can be excited and (b) not exactly The Green Zone for Microsoft. OOPSLA has faults -- big faults -- but I know that it's a place where I can get my assumptions challenged and my brain stretched.
I'll just leave it at that.