Good analysis.
I think the general rule is that, when a station retains its format, departing staff is not allowed to do a swan song as it casts a negative feel to the daypart. Sometimes, though, when a station is changing format, the departing staff is allowed to say goodbye.
The best "farewell" I have heard was the ending of the rock format when EMF entered Los Angeles with it's English language "K-Love" (LA has both a Spanish and English usage of that name, with the Spanish one being commercial and not religious).
I think it's interesting that Mike Kaplan (who replaced Kevin Weatherly) had a role in bringing The Woody Show on the air to KYSR, and will now have a hand on developing the new KROQ morning show.