All this discussion seems to be about work arounds for the real
problem. Namely, that the current hardware/software/protocols
can't handle what is actually a small number of routes.
Restricting announcements of new routes should be one of the last
things considered.
Here is one - for whatever reasons, we have a provider who can't seem
to correctly announce an aggregate and instead, announces several
specifics. Nobody says anything about this inefficiency - not to us or
to them. Some automated process watching for things like this and
sending an advisory email might help quite a bit.