It is smaller, but there are still two full scenes, a bit of the main story, a load of side content, some new functionality, rewritten portions of R5 text and grammar corrections, and multiple reworks!
After R5, I decided on two things: to stop giving release dates to the general public and to stop rushing things/portioning content - as was previously the case with R5.5. I have made working on SP my full-time job, and I plan on sticking with it for a long time, well beyond the day SP is finished. But without lowering the quality, the amount of content, or burning myself out just to meet some arbitrary release date!
She is currently still a work in progress! But soon!