I have been in a couple of AA test boardings, where they loaded window seats, then middle then aisle (after all the usual F, elites, families and old folks, Etc.). I thought it was great and sped things up a lot but never saw it again so I guess it wasn't a good idea.
As to the hot planes, I fly to PSP a lot and this summer SEA/PSP turn is on a 734. That one they simply cannot keep cool at all when loading at PSP.