I am proposing allowing live regions to be disabled. I'm planning to control this with the report dynamic content changes setting, which could be set in profiles as well. Ideally, you'd be able to control on a per site | per region basis, but that isn't easy for us to do yet.
The idea would be to speak live regions when this setting is on, and nvda+5 will be finally able to stop monster pages (pages that read live regions incessantly). PR coming to plum live regions from IA2 through to a callback first, please comment on this proposal.