If my memory serves me correctly the Forte comes with two new piano samples, a new Bosendorfer (German) piano and a new Yamaha (Japanese) piano. Perhaps you've chosen the German piano rather than the Japanese. There is a distinct difference in their sound.

http://kurzweil.com/product/forte/audio/

The rich piano is the Yamaha and the solo piano is the Bosendorfer. The Bosendorfer has a flatter, warmer sound.

I am familiar with the Yamaha Workstation pianos. Played those sounds too, for many years. While switching to a Kurzweil, the problem is, the Yamahas somewhat "ruin" your hearing experience.
The Yamaha sounds are heavily pushed with their presence and make you feel sure, they "cut" through the mix. Especially in live environments. This works to some degree, but trust me, it's faking something and supress other components of the overall sound.
You don need different samples in a Forte, you simply need to push the presence with your EQ to get the same structure and effect. But I would not recommend that, because it's walking the same path further along, and that is no good path.
If I listen to or play a Yamaha today, after several years with the Kurz, I find those sounds unpleasant and intrusive. And even more - somewhat flat with little depht. When I started with my Kurzweil, i found it sounds dull and too dark. It's not, it sounds more natural and sits "Inside" a mix, instead "on top" of it. The sounds in the Kurz are programmed with much expertise and obviously with a professional environment in mind. The Yamahas (and other brands) are done in a way to "wow"! your ear, but that's earcandy that smears your experience and misleads you.
You surely can get something similar on a Kurz like you know from the Yam, but I tend to advice to try not walking this path further. If you don't hear yourself in a live mix, there is a problem with the mix, not with your pianosound.

I played with a Yamaha S-90 for years and then graduated to the Casio PX-5S and then to the Forte. I bought the Forte as a "swiss army knife" board so I wouldn't have to bring two boards to every gig. I, too, found the pianos lacking on the Forte and found myself wanted to bring my Casio board to the gig instead of the Kurzweil. In fact, that is what I have done. I also found that the organs on the Forte were ok but not good enough. My current set-up is a Roland VR-09 on top and a Casio PX-5S or Casio PX-560 on the bottom. The Roland board is light years better at Hammond sounds. And I like the Casio pianos better than the pianos on the Kurzweil. At this juncture, I am looking at the Korg Grandstage which appears to be a better "swiss army knife" single board for live play with stronger piano sounds and organ sounds. I think that Kurzweil excels in its orchestral sounds more than other boards. It also is highly programmable for those who are so inclined and has a huge bank of sounds to choose from. Its electric pianos are also very good. In the right band, the Kurzweil Forte is outstanding. For me, I am disappointed. I clearly would not use the Forte for solo work or jazz trio work. Don't tell me that the Kurzweil pianos are better than the pianos in the Yamaha CP-4. If Yamaha knew how to put a decent Hammond organ into their pro boards, they might get my business back. I am not brainwashed as you suggested to the previous person who commented. My ears and my fingers on the keys are my guide and I know what I hear and how I feel when I play. And I have played both acoustic and electric pianos for decades playing solo and in various groups.

You might want to check out the Yamaha Piano for the Forte from the Sounds4Kurzweil guy. His site is under construction but to check out what he is capable of he made a 40 MB PC3K file of orchestral sounds that he released for free on Facebook sometime that IMHO quite impressive!