If you can't do actual in/on-ceiling speakers, my first inclination is to try the Klipsch add-ons (can you do 4 for both front and rear?). I think the soundbar technically gets you a complete 7.1.4 system, but I really don't know how good the speakers are, and the subwoofer won't be as good as the one you have, definite downgrade. I think soundbars can be pretty good (as I've seen reported here by a few people), but I wouldn't do one unless space literally forced me to. The Atmos add-on modules *can* be good, but the environment and positioning have to be correct, and most concur that they are simply not as good as actual architectural speakers.
Soundbar systems like this are attempting to do something similar with bouncing, and will be dependent on positioning and room conditions. In a perfect room - could be surprisingly good - but me personally, I'll stick with a traditional system that allows me to tweak it more readily. Keep in mind too - physics of small drivers vs. large drivers - a sound bar will not compete with those towers of yours.
