This is the sort of post that I can read without looking at who posted it, and still know exactly who posted it!
(which I consider a good thing, as I know very few people who smoke, and even fewer who are vocal about it!

)
I would assume that BA have little interest in the London to Edinburgh market and are running the flights primarily for connecting passengers. (If BA persist with their plans, then I would hope that those connecting passengers would look for alternatives!)
I would only really consider Luton for arrivals, for which it would be fine for me as when I used it (once, from Bergen), I found it relatively easy to get to the East Coast Mainline, compared to Heathrow, as I was able to get a bus to Hitchin, to head north via Peterborough (had I stayed on the bus I could have had a single change at Stevenage onto an LNER stopper).