OK, I just need to clarify something important since it seems a lot of people here aren't familiar with how old Strath and Scholo used to work; they were always tuned for 5 players. And same goes for UBRS as a 15man raid, they never really nerfed UBRS significantly except for removing a few spawns. The extra 5 player spots were for extra leeway.
They were never made to be raids, the only reason why the cap was higher was because of a design decision they made back then which was to allow extra players to join in if the group was otherwise full. This backfired, it turned out to be a lot faster to just zerg the instance with 10 players for loot instead of going with 5, which turned it into a zerg fest which ended up being far too easy.
Again, Strath and Scholomance has always been tuned for 5 players, even back at release. Just because some list of things you didn't know about vanilla said the cap was higher doesn't mean it was a raid in the technical sense. You could 5-man it back then.
Source: http://blue.cardplace.com/cache/wow-gui ... s/4573.htm
http://blue.cardplace.com/cache/wow-general/3737297.htm