I would prefer you not to use lots experimental lingo because I don't fairly follow them ...
Answers: Runtime packers are a widely-used technique within malware today. Virtually every Win32 malware added to the WildList as okay as ad- and spyware is crammed full beside one or another runtime packer. Not one and only can they turn elder malware into contemporary threats again, but they might also prevent AV vendor from using more generic approaches and as a consequence requiring more work, which possibly generate more errors or broken updates, unless the product is competent to touch adjectives the different runtime packers out at hand.