Honestly, anyone who thinks a S10 is not powerfull or fast enough should really get a FJR instead (same aplies for the GSA). The S10 has WAY more than enough power and speed for it's purpose as a big dual sport. Heck, a F800GS is powerfull enough if you used the engine and gearbox the right way.
The only reasons I use a >1000cc bike is that I can think less about gears and RPM's, I can get in more stupid situations, overload the bike with crap more often and carry a pillion easly, in sum, because I'm lazy.
About the ABS, and for all who criticize the S10 sistem, PLEASE go to a dirt or deep gravel road and put all the power on the front brake, then tell me something. Keep in mind, not everything that's good on a 120kg dirt bike is good on a 250kgs one. Different contexts need different solutions, and an intelligent ABS is one on such big bikes