You're right in that it would be a chaotic/crowded mess if a whole bunch of airports suddenly sprouted runway extensions.
But that's not what I was suggesting. In your original post you said "Once the user selects the airport of choice and presses the "Direct to" button...". That's what I was responding to.
If you were meaning my other Wish List suggestion -- that's also not what I was requesting. I was asking for iFly to highlight the recommended runway in the list of runways (and/or on the display of extended runways) when the user requests Extend All in the Extend Runways dialog. And how you get to that dialog is by selecting an airport. There is no Extend All for multiple airports (though you can have multiple airports with extended runways if you do them one at a time).