* Best preventive maintenance is what you're probably already aware of. If the window is ice-stuck (assuming you live in the north) free-up the window some other way than with the window motor. And, in general, when the window is up, tell the kids not to keep pushing the switch.
* If you look at the window regulator action with the door panel off you'll notice the flex in the sheet metal at closure. The motor and gearing make for a powerful drive (and the motor doesn't know when the window has made closure contact). I personally think that MB could make the motor a little weaker or change the gearing, at the same time that they strengthen the regulator pivots.