The security as new functionality is not really an issue to keep PCs running relatively safe. The argument that ECC is a new functionality and not a security patch comes to mind. That was a fair argument and people still had RSA. The underlying security breaking is not really an issue today as far as I see it.
The actual deal breaker are bugs who can be exploited and need to be fixed. And while its unfair to expect bug free software, fixing them is not new functionality.
The actual deal breaker are bugs who can be exploited and need to be fixed. And while its unfair to expect bug free software, fixing them is not new functionality.