I think you have a wonderful tone, great for the style you have chosen.
When I first started to play jazz guitar 20 years ago, I was really into Pat Metheney, George Benson, and Earl Klugh. I guess these guys are similar to Dave Koz and Eric M, in that respect, that they were the new "smooth' jazz stars. I wanted to play like them, but I order to get that sound totally nailed, I had to go back to their influences; Wes Montgomery, Charlie Christian and Django. It was a great journey that taught me a lot, and along the way I discovered some fine alto playing, which is why I am here ;-)
It is the same with these "new" alto players, as Madgrocer pointed out, I think if you want to go to the next level and innovate, you have to go back a bit in time and start emulating the guys that influenced Koz and Marienthal
You refer to Coltrane in your profile, so I am sure you are going back, so perhaps ignore this advice!
Dave Koz et al are great players, but I think you will get a lot of mileage by listening specifically to the ballad playing of by past masters like Paul Desmond, Art Pepper, and tenor players like Stan Getz and Ben Webster. Try and incorporate some of their improvisational ideas into your playing and you will be onto a winning formula!
I think you have a great future, lovely playing!