I just thought of another prediction (or symptom) which indicate that the current announcement scheme is toxic (shallow-first).
I would postulate that many nodes (perhaps those not traffic- saturated) would have to intermittently re-announce as they slowly loose their connection to the network. A rolling effect by the 'good routes' being replaced by bootstrapping nodes. Do we have any data (or theories) or the expected (or actual) re- connection rates? -- Robert Hailey