You are wasting our time. There is clear consensus to deprecate SLs. They
were a bad idea, and people realize that now. Your attempt to justify the
burdens they place on the network, on apps (including DNS), on routing hasn't
made them look any more attractive. The best justification you've been able
to produce for keeping them is that they're supposedly already deployed. Of
course that deployment is insignificant compared to the future use of IPv6.
At any rate, nothing is likely to stop legacy products from using SLs if they
want to -- the point is to make certain that future products (especially apps)
don't have to deal with them.
What you have totally failed to do is explain why site locals and the burdens
and complexity and unreliability that come with it are in the best interests
of the Internet as a whole, as opposed to the interests of some company that
wants to sell crippled products to its customers.
Site locals had their chance, and failed to justify themselves. Taking them
away results in a vast improvement to IPv6. It's time to move forward.