I admit to only reading part of the article, but it seems like the author just wants a media scripting language, not a "programming" language, which AS3 has become. The sandboxing and unloading are legitimate issues, but have nothing to do with the language.
I wouldn't necessarily be against a wholly different language for use in the timeline, as I prefer not to put code there anyway, assuming I have to use those ugly Movieclips at all. I could see something terse and elegant, eschewing the AS2 prototype nastiness, being useful for animators and light programmers alike. I think the biggest barrier for most is the new event model. Adding listeners is a bit verbose for those used to simply overriding an on() method.
I wouldn't necessarily be against a wholly different language for use in the timeline, as I prefer not to put code there anyway, assuming I have to use those ugly Movieclips at all. I could see something terse and elegant, eschewing the AS2 prototype nastiness, being useful for animators and light programmers alike. I think the biggest barrier for most is the new event model. Adding listeners is a bit verbose for those used to simply overriding an on() method.