The limiting factors up front for me after the OME front packs were the brake lines--they weren't really long enough for any droop. They even got in the way of the spring installation. I went with some longer braided ones--they're too long now, but they don't limit anything (I have pieces of bike innertube bungeeing them up to the undercarriage so they don't get snagged on anything.
The OME front packs with the OME front shocks (or other shocks the right length) on the original mounting points provide quite a bit of flex up front, especially with the front anti-sway bar undone. The track bar that runs front-to-back and connects to the axle is a little bit limiting. I had a mentor of mine put a swivel in the middle of it for me. It was cut in half in the middle and then a brass, threaded fitting was brazed onto each end, with a threaded collar connecting the two. Now it still controls axle-wrap but the ends can rotate so they don't limit flex.
I agree that too much flex can be a bad thing. With the suspension systems that have crazy amounts of droop, they may keep the tire on the ground but there's so little weight on the drooping tires that that it doesn't do much good from a traction standpoint. They also often don't offer much yaw control, so they can be scary on side-hills and off-camber sections.
