Am I Better Off With Limited Low Frequency Speaker In A Small Room?

You do have an issue in that you have a square room, which will create significant bass reinforcement issues. I had a similar issue with my floor standers that go down to 28Hz, and short of bass traps or DSP/room correction the only way I could somewhat alleviate the issue was to pull the speakers out 5’ from the front wall but there was still slightly overdone bass.

I would highly suggest going with monitors and incorporate two small subs that have their own integration software (i.e. SVS SB1000 Pro) that will let you better manage bass in your room and greatly improve your overall performance while giving you a true full-range system in the process — best of all worlds solution IMHO. I think you’re absolutely on the right track by also using GIK products and I would take their advice for your challenging situation very seriously as they really know their stuff. BTW, let us know if you need/want suggestions for speakers/subs if that might be helpful — lots of wisdom, experience, and hard-won knowledge here that may help you make more confident purchase decisions. Hope this helps, and best of luck.

I'm not a fan of subs. There can be a discontinuity in tonality. I have never heard one in a room where I didn't prefer listening to music without it. 

Due respect, you’ve never heard decent and properly dialed-in subs.  When properly integrated you’re not even aware subs are even on much less hearing any tonal discontinuities (sub’s crossover and/or volume was probably set way too high if that’s the case).  When subs are well integrated it’s the exact opposite of your experience — you won’t listen without them.  BTW, subs don’t just provide bass.  They dramatically improve overall imaging and soundstage and greatly enhance the sense of space and detail in a recording, and when you turn the subs off everything just collapses.  And with 40Hz as your lower limit you’re missing out on a ton of the musical experience.  Just my experience FYI.  BTW, don’t take my word for it — order a pair of SVS SB1000 Pros and see/hear for yourself.  They offer a long in-home trial and pay shipping both ways so literally costs you nothing but a little time.  My $0.02 FWIW. 

I expect most audio salons don't have a clue how to set up properly.

+1. 

If your cubical room is a problem you may want to try a diagonal setup in your listening room.

I completely agree and I believe the OP is already doing this.  At a show in NYC Jeff Joseph was showing hiswonderful Pulsars in a very small room and had them set up like this to great effect and definitely made the most of it. 
 

Downside is that the speaker can sound bright but at the same time, not all that airy in the soundstage. And tonally, it sounds a bit gray. Nothing is so harmonically fleshed out that I believe it’s real.

This largely seems odd (except the airy part) and begs several questions:

- What’s the rest of the equipment in your system?

- What sound characteristics are most important to you?

- What improvements are you looking for over your current speakers?

- Where are you located and what speakers do you have access to?

- Can you purchase from the US?

You really haven’t given much to go on here, and the more info you provide the more effective and productive this post will be.