Speaker size and soundstage

Such fantastic input; greatly appreciated! 
I changed the setup yesterday by swapping out entry level cables with higher end cables. The dynamics in both speaker changed dramatically with both opening way up. 
The Tektons now have much greater extension, but are a little sibilant (may mellow as the wire burns in). The Dyns  soundstage is expanded substantially and they now fill the room and feel, perhaps, more balanced than the Tektons—more listening needed!

So to confirm other comments, the system and electronics do of course make a difference here, and in my case the speaker wire seemed to be an earlier limiting factor.

+1 knotscott - yes, drivers that play well together in an inert enclosure,  crossovers with a deep symmetrical anti-phase at correct crossover points that reduce to the point of elimination of breakout from drivers. The baffle design and driver basket interactions with the baffle, correct cabinet size for the drivers not the room.

Yes, knotscott same page here.

w123ale - shhhh keep that on the low low bro, speaker wires can't possibly make a difference **wink** (sarcasm intended)

I think people have different definitions of soundstage. IMO, it means a speaker's ability to portray the musicians in the places they were put in the recording so instruments can be identified by location.

That sounds more like what I'd call "imaging", namely, the precision and accuracy of the musicians' apparent placement relative to each other ... and within the soundstage.  I think of "soundstage" as the 3D space bounding this placement.  Presumably, most audiophiles want a soundstage with the greatest apparent breadth, depth, and height achievable for playback of any given recording. But presumably they also want sharply defined images, along with the illusion that the speakers disappear within the soundstage. 

The Bose direct-reflecting design can achieve a big apparent soundstage even from very small satellite speakers along with a single subwoofer. That may sound impressive and pleasant at first listen, but I wouldn't expect very precise, accurate imaging (or frequency response) from that approach.  Admittedly I have not listened to Bose speakers for many years or in a wide variety of settings.  

On the other hand, I had a pair of Totem Arros, which are small floor standers with a reputation for excellent imaging.  I found they did indeed consistently produce a sharp center image and the speakers did indeed seem to disappear within the soundstage. However, the soundstage was not especially wide, deep, or high (at least not in my set-up).  Furthermore, the skinny boxes could only accommodate 4.5" woofers, which limited the bass impact.

Lots of factors and trade-offs. 

The monitor audio gold generation 5 and platinum generation 2 both have incredibly huge three-dimensional sound stages.