Bigger drivers = bigger soundstage


Ideally, I don’t like to be aware of a speakers location in a room and like having sound being well centered for tv/movie listening.  I have two listening rooms and the one with larger drivers (older) fills room so much better vs better speakers (newer) with smaller drivers.  Room acoustics favor larger driver speakers.  
Seems dispersion is better.  The larger driver speakers do not image as well but very enjoyable to listen too. 
So now I am upgrading the smaller driver speakers to better and larger driver speakers and it follows a larger speaker cabinet also occurs.

all speakers herein are from same manuf. 
emergingsoul
Driver size (physically) is the answer to the OP question. The manufacture, SEEMS to hold to the same principal, without knowing the OPs actual speakers...

The physical size of a typical cone / basket speaker is the only physical limitation of the actual driver... (materials may very) AGAIN 5" drivers don’t do 20 hz any more that 12" drivers do 2500 hz well. I don’t care how well it’s manufactured or wave guide added. They (12") are limited physically.. to lower frequencies, just like smaller drivers are limited to higher frequencies..

The exception is multi driver application.. lobing is an issue then..BUT by careful design (length of the array) in comparison to room height, and XO design ALL of that is just that, "designed into the speaker.". A bad design goes a long ways. Just like a good one does...

Correct driver and application ARE the way to better sound..from the "BOX" perspective only... Nothing else.. No rooms, equipment, cables, tweaks, bad hearing, good hearing, or a change of dippers, matter. ONLY the correct application of a given driver..

When I say correct, I mean I check if the driver lives up to the manufacture claims.. maybe 50% of the one I’ve tested do. Seas is one of the best cone drivers I’ve ever used, just a fact for me.. I wish I could afford their drivers in every build.. Just top notch..

Driver manufactures have been trying to design past it for years... It is just a physical fact... THUS.. Planars... Convex Domes, Rings, and Electro Stats...

I’m not just another pretty face, I’m actually kinda smart...ebm (self proclaimed of course). I know, I can build a better speaker enclosure than most of the older designs.. the newer CnC stuff.. Tough to hand craft some of the designs.. Really no need to . It is mostly window dressing anyway...

Aluminum, @Corian and exotics being the exception..$$$$$ I remember a single log (TREE) went for over 1.2 million just for the veneers. 30 years ago.. I though I spent money that day.. 8-900.00 dollars.. LOL I was just blown away.. For a church build of all things..

Regards
My speakers use a 12" driver, have 360 degree dispersion, a wall to wall soundstage, and can be tuned to any room large or small. They are special! Just saying.
The size of the baffle in which the driver is mounted is a big part of this too.  There have been plenty of A'gon threads arguing about wide baffles vs. narrow baffles.
Smaller drivers with similar bass extension have lover sensitivity.
Lover sensitivity drivers have more thermal distortion and compression. 
You can do nothing against laws of physic.