I don't know what kind of broken you are reffering to, but it's painful to see what "they" (the idr wg) are doing with BGP. Most RFC contain something like: "since BGP is such a widely used and stable protocol, let's add more stuff to it!" And the go on changing semantic of existing encodings in a way that forces unimaginably hairy hack unto any reasonable existing implementation (see flowspec, see multiprotocol, see add-path, ...)

I'd rather have tens of tiny protocols running on network, that one such BGP bug-carrier.