BF - You seem to have a very poor memory as both of your EDI questions were replied to in one of your previous topics two months ago: "EDI Approaches".
Although EDI now has a full length taxiway, we still don't have RET's; hence why we still need 5 to 6 miles between landing a/c.
The point about strong headwinds is an interesting one. If we're dealing with medium-size jets (73's/75's/A320's etc) then I agree that final approach spacing could be reduced to 4.5/5 miles. However, as soon as you get Dash 8's, D328's and Saab 340's landing with a strong headwind they end up virtually stopping at the midpoint and then taking a considerable amount of time to vacate the runway. At times like these 6 mile gaps is almost not enough!
As EDI gets busier we're going to need to utilise the runway far more efficiently, employing similar techniques to Manchester and the London airports.
What we need is another one of those Pilot/ATCO forum thingy's where you can tell us what you'd like to see and we can tell you why it ain't being done.
Feel free to drop by the tower anytime for a vist.
Swift