I don't know if folks have any tricks for manipulating the cymbal panning...maybe I'm just not seeing it in SD...but it kinda sucks that the cymbals in most of the EZX/SDXdrum packs are always panned fairly hard left/right.
Now I will say that I don't ever bother loading all the alternative ambient/room mic samples that come with packs, as I don't see much use for them, I just like to use the basic installation for drum packs...so if there is some alternate mic positions in those alternative samples that provide more options for cymbal placement in the stereo field, then someone please tell me, and you can ignore the rest...but I doubt that ambient/room mics will change what the OH mics are picking up, and you really can't do without the OH mics as part of the drum sound, IMO.
Occasionally, there's a pack that has an additional set of cymbals positioned more toward center...but iin most packs cymbals are usually the hard left/right...and quite frankly, that's become a dead giveaway that your drums are coming from a drum sample library.
No matter how meticulously you craft your drum grooves and sounds...as soon as the cymbals are hit...people know the drums are coming from a *sample library*.
I know it's possible to go mono for the whole drum kit...but that's not what I want. I want a stereo drum kit, but I would like to move the main left/right crash cymbals more toward center on some of my mixes....so that at least from song to song there is some variety...instead, every song that I use Toontrack drums on, the cymbals have almost the same hard left/right placement.
I've used my DAW editing capabilities to isolate and adjust the width of stereo image of the cymbals...but it's a real PITA, and it affects the entire OH track, so I can only shrink the OH width so much.
It would be nice if you guys offered some alternatives to the hard left/right placement of the crash cymbals in your drum packs. Maybe include some more isolated/focused cymbal mics...or just move the cymbals in, and offer two sets of OH options - cymbals hard L/R and cymbals half way L/R...or just add more cymbals, and have two on each side (two wide, and two closer in) in more of your drum packs, especially the ones with larger kits.
You guy focus on recreating classic drum *kits*...but the reality is that most of us are mixing/matching drum pieces from various kits...so it won't be a big deal if you add some more cymbals to a "classic" kit pack, even if the classic kit only used one. 
Otherwise...I love the sample packs (EZX and SDX) and love Superior Drummer. It has changed how I work and how I record...and I can finally get drum grooves and fills exactly how I want them, without debating with a drummer. 
Thanks!