Someone will doubtless have the actual figures, but doesn't the 767 in Euro configuration have pretty much the same capacity as a BA 777, all of which are in Long Haul config ?
DME is indeed a high yield route. The competition with Aeroflot is less than you might think as they operate from SVO, and the two airports are diametrically opposite across Moscow, it takes about 2 hours to get from one to the other, and passengers seem to make their preference more than anything else based on where they are going in Moscow. It's a big city and both airports are far out.
All the Aeroflot A310s and 777s seem to have been returned to the leasing companies now. Aeroflot stick to the A321 for London, supplemented by a few Il-96 flights. There are up to 4 A321s on a Saturday, peak day on the route.