The most obvious change has been a change in ownership at EDI which has resulted in a far more competitive and successful commercial environment. Flybe Nordic might be a contender to operate the route with E190s as opposed to A319 before, and hopefully with an increased frequency over what was offered last time.
There are many reasons to be optimistic that Finnair could return to EDI with much greater success this time. If the airline is actively talking to the airport then that is surely an encouraging sign?