Whats that saying about a carpenter that blames his tools?? :p Really, if you drive in winter than you need winter tires. Mercedes has done their bit with 2nd gear starts and ASR but they can't account for every driving situation.

Up here in the snowy North, two sets of tires and rims are the norm. If you experience city driving than "ice radials" of stock size are OK. If you take to the ski hills where deeper snow is expected, than more aggressive tread one or two sizes narrower than stock are advisable (seems odd but results in greater traction due to more veh. weight per sq. inch of contact patch).

A shovel and survival kit in the trunk should accompany any highway trip and don't write any cheques with your right foot that your insurance company can't cash.