Malone:
I completely agree about words in the clue being part of the answer - I can accept one-letter words (A or I), two-letter words I can just about tolerate at a push, but anything longer is a no-no.
I had a discussion a while ago (possibly on this site) regarding the 'currency' of cultural references, in the context I think of a clue which made reference to the TV show The Prisoner. My view is that the passing of time is not
directly relevant, as fame can be amplified as well as diminished by its passage (I'm thinking here, say, of Van Gogh, or the aforementioned Prisoner, which was sufficiently well-known to be parodied in The Simpsons many years after its last transmission).
What I think is important is whether at the time the clue appears the person/programme/film/whatever is the subject of a reasonable level of public awareness. Mozart hasn't written anything decent for ages, but I'm sure he passes the test; Tony Hatch (a household name within my memory) definitely does not.
I also don't think that the 'level' of culture is relevant - a soap star may be known to far more of the population at that particular point in time than a classical actor. Repeated use of references perceived as highbrow runs the risk of reinforcing the idea that crosswords are elitist.
Regarding this particular clue, I felt the series title Gunsmoke would have been OK in the US, where it is regularly retransmitted, but not in the UK. I know nothing of the E-Ring and would never, ever have used its title in a puzzle even if I had. A truly weak clue.