You guys are placing way too much thought into "signal" and "coverage". While it does matter (and in this case 1010's sucks compared to 620 and 1040), the intent and trend here is to move programming from the AM to the FM side because there are fewer and fewer people listening to the AM side of the dial. So while the argument can be made that programming on a station like AM 620 does not have to make the move to FM simply to overcome signal issues; it does increase the chances of more listeners and more often. Example... Let's say I'm a 28 year old male that likes rock, country, and "hot talk" and I'm listening to 102.5. They go to commercials... I don't click over to the AM but instead punch up my other FM presets which could include 98.7 The Fan, 98Rock, WQYK, and any other FM stations that cater to MY tastes. The longer you wait to make the move to FM the more work you'll have to do to re-image when the others do it before you.
WFLA is hanging in on 970 but as we've said many times on this board, it's only a matter of time. As for WDAE, they're well established on 620 and the signal is solid anywhere in Tampa Bay. And let's remember, it's about Tampa Bay... not if you reach Ocala, Orlando, or Ft. Myers. However, as direct demographic competitors begin appear on the FM side, their ratings could suffer. Just my opinion of course.
PS.... and one more thing, Clear Channel isn't gonna kill off good revenue to replace it with less. Unless you have a dog on the FM dial (which CBS does with 98.7), it's not worth making the move. I think you're gonna see WFLA pop up on all these FM translators soon. Go ahead and run a search for "Tampa" on Radio-Locator. Lots of recent permits issued in just the last month for modifications for 94.5, 95.3, 105.9, 103.9, and even a 104.3 in Riverview. Something is going to happen.