I know what you mean Benn. On nordic winter-tyres it's even worse than on your central-europe winter tyres I think.
For me it's not possible to drive the car unless you drive in sport+ or traction mode.
I can drive @ 80km/h in eco-pro-mode with cruisecontrol engaged in 6th gear (manual) on a perfect dry road with 100% grip. If I then hit the button on the steeringwheel to up the speed a notch or two, the car will start accelerating slowly but within a second or two the antispin-symbol start flashing and the cruise-control is dis-engaged with some error displayed on the screen stating that the cruise was disengaged due to the loss of grip or something in that direction. Doesn't happen everytime but still often.
so even at the most gentle acceleration on super-low-revs on a road with perfect grip a non-existing/imaginary wheel-spin is detected. Overtaking another vehicle is unthinkable without entering traction or sport+ mode first. If one would attempt an overtake without taking those actions first (traction or sport+) they are in for quite a surpise when they throw themself out in the wrong lane, stepping on the accelerator expecting to actually have a decent acceleration but rather find themselves left with the engine strangled down to 1 hp and a flashing antispin-light making the car hardly accelerate at all even on a road with perfect grip.
It's the ultimate death-trap really. If one want to have someone killed, just lend them your bmw and encourage them to go experience the awsome driving dynamics/ultimate driving machine on country-roads. "hey, overtaking vehicles is really effortless in this quick and nimble car, you should try that"
quite a dissapointment... I guess a properly working anti-spin-system in both summertime and wintertime is too much to expect from a "premium bmw".. just like having a car without rust in it is too much to expect from bmw these days.
but to get back on topic; perhaps this is not the problem you're having? when I disable antispin I find the actual grip to be good. Do you have problems getting the power down even in traction-mode or sport+ ?