Whether WPST and WDAC should coexist, or WZZO and WAYV, or WLEV and WZXL, or WCTO and WSOX, or WNNK and WAEB-FM, is beside the point.
Those allocations, which happened many years ago, would not happen now.
With respect to 94.9, the nearest co-channel is WRBT in Harrisburg. As a class D, WRSD Folsom (Ridley HS) should not be an obstacle. The nearest 1st adjacents are WAYV, WZZO, and WDSD. Just like the 96.1A thread on the Delaware board, a full-power (A or B) 94.9 allocation anywhere in the Philadelphia DMA has a snowball's chance in hell of happening. Check out the the contributions of Scott Fybush and w9wi on the Delaware Board's 96.1 thread.
Others are suggesting everything will stay just as it is. Perhaps for a little while. But what are the naysayers saying? Such ideas as: Save AM for the sake of DXers (Not enough places to hear "Coast-to-Coast AM" every evening); Save the music on FM (Lady Gaga is not on enough stations now!); Allow for the proliferation of other slam-dunk formats (if done correctly!!!) like standards, comedy, pan-flute music, non-stop poker tournaments, sea chanteys, and all-Scandinavian death metal (stab, stab, bork, bork!).
In the short-term, CBS may feel that it can wait. But, I personally think there are two opposing forces at play with respect to CBS' potential long-term response to news on 106.9. The one that favors a move soon is that buying a new station is a better deal now than it has been; The one that opposes is that the bottom may fall completely out of the market at some point in the next few years, and an even better deal will become available. Who knows which is correct?
There is no new full-market-coverage allocation scenario. And this market would not appear to be able to support it anyway.