After having HP guys view our controller & generator servers in operation during load testing, I have come to the following conclusions:
1. The ">80 CPU" issue probably existed prior to our upgrade to LR 11.52 & prior to upgrading our servers to Windows 2008 R2. I have no proof of this; but am about 89% satisfied that our generators were overloaded, for the same scenarios, before these upgrades.
2. The "real" solution will likely involve upgrading our load generator virtual machines, increasing their CPU capacity and/or memory, and same on the controller server; plus, maybe even increasing number of load generators we utilize (currently, we use four).
3. We might also need to revisit manner in which we test some of our apps, to assure scenarios give good analytic results without overloading generators' CPUs. It appears ">80%" error occurs when scenario slams generator(s) with more virtual users than can be processed simultaneously.
4. In future, at times, it may prove valuable to include at least one LG's stats, for CPU, etc., in output, so this gets included in analysis for specific load tests-- to assure LG's aren't overloaded, in resulting report (added via System Resource Graphs, Windows Resources, on Run screen in Controller).
***Thanks for Boris & team for assisting on this!