I believe it WOULD be a wise idea, especially because it would alleviate te overcrowding on the QB IND, and it would serve neighborhoods which have no subway service today. The reason these neighborhoods aren't clammoring for more mass transit is because they've gotten used to not having it. Build the line, and the demand WILL create itself. Glendale and Maspeth have been populated for years by older retired people/couples, or people who drive to/from work. A new subway would make these areas more desirable for working class people.
That's this reason that the NIMBY's killed this plan off. They don't want these kinds of people (minorities) in their neighborhoods. I'm loathed to use the race card, but it's unavoidable in this subject. Maspeth and Glendale are predomintly white.