Ok, a little harsh sounding, and maybe a little critical to boot, but most of above is pure hoggy-washy...
The last statements refering to using the "short wall" setup for getting a huge soundstage are not fact, in and of themselves. Infact, as an acoustical engineer, I'll tell you that the front wall reflections have much much less detrimental affect than the boundaries between you and your speakers!(sides,ceiling,etc). Usually, a minimal diffuse/absorb solution up front will deal with any problems there.
Without any applied acoustical treatments in small rooms, it's usually easier to get a better soundstage and imaging using the "longwall" setup...all things considering. If the rooms are too narrow however, there's other challenges in bass modes and proximity to the front speakers that are considered however. If you do do a short wall setup, you'll either need to have the speakers "in a bit" from the sides, and be sitting closer in approximation to the speakers for a good soundstage and imaging. Otherwise, you must deal with reflections, preferably more diffusion in small rooms, going to more absorbtion in larger rooms, as is most often the case.
Of course, it's all a balancing act with acoustics. But you can get a massive sounding accoustic, with severe acoustical modifications and applicaitons. Mainly, you need to absorb all the excess bass in small rooms, which often aint happenin'! Therefore, there's too much bass overhang and reverb. Then, mate that with the case that most people aren't getting anywhere near flat response in small rooms from their seating possitions, don't/can't properly adress "Q" in the room, nor deal with reflections and balancing diffusion/absorbtion/etc right, and have a seroiusly challenged setup all around, and it becomes a near impossiblity in most cases to get a world class sound!
Oh well...you can always higher an acoustical expert.......
In short
