Allowing repair of our engines is a great idea. I see no issue of performance here, only allowing us to save blocks
I do not see any need for a gas rule at this time.
I do not know enough about the spring issue. If it improves our reliability, I support the idea. I have had several valve spring failures. Of course, I don't know why they failed but if some other spring can avoid this known problem, I say wonderful.
As for the concern about reving higher, who cares. Our engines quit making power at 6K or so but if better springs can prevent an issue on an over-rev, again, great idea to protect our engines. I know of many engines that have been damages due to drivers making a mistake and we should try to prevent as many of these as we can. Again, I do not see this as a performance issue and it should be considered.
Jim