I am indecisive about choice due to room size

Adding bass.... not an upgrade.

What I would do, have your room professionally treated by GIK. If you haven’t already, it will balance your bass to mid/treble energy better, in addition to improving clarity and imaging.

Do that long before you think about switching speakers.

I cannot tell you how many people do this and discover how much bigger their speakers sound. 

I'm in a basement space which is bigger than your room but with low ceilings. It absolutely could not accommodate tower speakers -- Focal 836, Martin Logan ML 60s. Bookshelves with a sub was the ticket. Easy to play with placement, too.

You can toss all the above bad advice. Some of it is outright plain wrong. Adding bass for example is exactly what you need. Your biggest problem is not size but being square, 12x12. But 16x16x8 would be bigger but at least as bad. Simplistic thinking combines with poor understanding. People hear the obvious boomy bass in a room like yours and assume too much bass so solve it with small speakers. Wrong.

I wouldn't go with any of the stuff you like but I wouldn't hesitate a moment to get better speakers simply because they're "too big for the room".  

Regardless of speaker you're going to want to control the lumpy bass identical dimensions causes, and early reflections. In that order.  

Lumpy bass is best solved with more bass, not less. Using multiple subs will allow you to put them in different locations to excite different room modes and ultimately achieve much smoother bass. Duke himself, owner and speaker designer at Audiokinesis, says the benefits of multiple subs are even greater in small rooms than large.

Just one of the ways people misunderstand the realities of the situation you're asking about.

Will the speakers fit in the room? Will you be able to place them with drivers at least 3 feet from walls and ceiling? Then they are not too big. 

It may work, but you may need to work on the room, too.

Smaller speakers have their own advantages, but bigger is not necessarily worse. Good luck and have patience.

Easiest way to get good sound in a square room. Use active speakers with digital control like Genelec, Dutch and Dutch,  Kii, new company GGNTKT might be another. There are others you can research. I've used passive speakers with outboard control it helps but isn't as good. You'll need less room treatments and get better results. One thing you don't need is a passel of subwoofers in that small room you can get all the bass you need for music with a  couple of Genelec 8361A.