Not sure if this fits here, but with all the hoopla about the BQX streetcar, it got me thinking that there should be an LRT or streetcar style feeder system in NY running alongside/replacing some bus routes or running alongside freight/commuter rail.
The Bx.12+ could be a streetcar running from Inwood-207 Street, omitting the section to Bay Plaza along the NE Thruway which could be made a shuttle
The portion of the Q.44+ from College Point to Jamaica could be made into a streetcar, which would make outer borough travel easier.
A LRT or streetcar along (not on the tracks of) the Lower Montauk or Bay Ridge Lines of the LIRR would also be cool.
Might be improbable, don't know a lot about LRT/streetcars.