I first thought it was the B upgrade to Platinum that was causing my projects to load so slowly. As much as five minutes. Then I experimented with removing VST's. First try was GTR, and that was the culprit. Without it, my projects load within 30 seconds.
 
I'm wondering it the coincidence of my plan coverage expiring on March 5 had anything to do with this new hidden feature. Perhaps, so I upgraded, uninstalled and reinstalled. The standalone version took about three minutes to fire up, having a good old time with its scanning. Now I'm watching Sonar do a VST scan that is slower than the Second Coming.
 
Is GTR going to survive this? I don't know.

Problem solved. A tech from Waves spent about two hours with me on the phone while he was exploring my computer remotely. The problem was a combination of a few bad registry items, and several redundant VST calls in Sonar. Why it came on suddenly, I do not know. It seemed to correspond with the B upgrade, but that probably had nothing to do with it. Mostly it was due to not being diligent about completely removing uninstalled software.
 
Anyway, it's fixed and GTR 3.5 remains my go-to amp modeler.