Seems like someone decided to revive an old thread, but what the heck...I might as well chime in.
Traction control, for the most part, is designed to limit wheel spin/sideways motion when it's not desired. However, 4 wheel drive/traction control/ABS is only as good as what's making contact with the road surface. If you have shitty bald tires, expect the worst.
I have a 2003 Limited V8. When I bought it, it came with newish Goodyear Assurance TripleTred tires. Absolute garbage on snow and ice. I don't know if I have ever driven on a tire that was as terrible, save for maybe BFGoodrich Rugged Trails. Goodyear even claims that they have an ice zone. Suuurrrre.
Switched them out to Goodyear Duratracs. One of the better all-around tires I've ever owned. Great in deeper snow. Good on ice. Winter rated if you need that for mountain passes/local laws.
All that said, I leave the center diff alone unless I'm in deep snow and want to maintain some wheel spin. Otherwise, the 4Runner can be a handful on ice. It will snap sideways making a turn if I'm too hard on the throttle. All that said, traction control and ABS will make little difference if you are going too fast on slick surfaces. Lowering your speed decreases your kinetic energy exponentially.
My best friend got a new Jeep Grand Cherokee last year. Great power, handles well. Until the snow hit and his factory all-season tires made it downright scary to drive. I let him drive the 4Runner and he did some hard accelerations on snow. Those same accelerations in his Jeep were impossible, he said. So, despite being 15 years older than his vehicle and lacking all the bells and whistles and Quadratrac and high tech traction control, it would easily out accelerate and out stop his Jeep.
Tires are the only things touching the ground. Spend your money wisely, take care of them, drive according to conditions.