[AM160]

t's difficult to understand why someone would choose the most inconveniently shaped part of a large multi-story building in which to place a studio.

A decision made by the breakfast management team at the time. The Studio was meant to be ground floor and would have been much higher.
One of the many reasons it went upstairs was because Peel (who own the site) wouldn't close the public footpath which runs around the outside of the building, nor could they guarantee security. The possibility of disruption was considered quite high.

It's not a small space, and as we saw with the temporary Sports set just down the corridor, stud partition walls can be taken down and/or moved to create a better shaped area if needed.

There are no stud partitions in SQ2. Studio 4 (current temp set) was made bigger by virtue of moving a "wall" but that space has never officially been a closed off room if you like. the flats don't go to the ceiling making it a bit easier to change.
SQ2 is an odd shape because of an apps room and aircon stuff. It clearly wasn't the gents toilet...