*** Warning, long read. My own winter experience.**
I run Nokian Hakkapelitta R2 SUV tires and im pleased with stability and control. Like people have mentioned, the understeer is common given the fact that the RAV 4 is pretty light in the front end (my 4cyl engine is the same engine used in the Corolla), and the front tires carry the lion share of the load in the all wheel drive system. In fact, the electronically-engaged AWD system only engages when turning, slipping, or descending steep hills to increase fuel efficiency (best in class, I might add).
Subaru's symmetrical AWD never disengages and, given all its rally accolades, is arguably the best AWD system in mass production. By the same token, we must also acknowledge the RAV4's recent success (Ojibwe Forest).
To follow the OP: Bridgestone Duellers are the kind of tires they put on production lines because they meet minimum requirements and are cost effective. They should never be ran in a proper snow trial unless your aim is to bobsled.
Ways to increase traction in the RAV:
-More evenly distributed weight (when I have my family inside I can notice more traction)
-Proper snowflake-rated tires.
-Avoid big snow ruts because despite our feelings of confidence, the RAV's a unibody construction (not body on frame like a Jeep Wrangler) and it responds in bewilderment to jarring movements.
-Slow down around that corner because it is not a perfectly balanced vehicle (high center of gravity, and the long wheelbase combined with a short track makes it want to throw momentum "over" the wheels). If you begin to slide gently apply power until control is restored.
-When stopping on snow or ice, the RAV has a proclivity to shift all it's weight forward given it's uneven proportions (I might need new struts soon), so leave room for breaking. I found this out the hard way as I once barrelled through an amber light like a paperweight. This is why people put sandbags in the box of their 4x4 trucks, to evenly apply weight to both axles. In the Rav, there's no beefy differential or driveshaft to offset the weight imbalance - leaving the front tires, rotors, and brake pads to carry most of the stopping force. Obviously, this is not ideal and puts strain on the ability of the ABS to work properly during abrupt stops in winter conditions.
Elaborating further; don't overload your tire's ability to wick away snow, water, and ice. By driving in heavy, thick snow with a compacted underlayer your tires effectively lose their traction altogether no matter how skilful you are. We've all jumped that mark a few times, and are quickly reminded of how driving is a responsibility as much as it is a right.
Oh, and if any of you noticed the chime that sounds when your traction indicator senses you are being a bit adventurous...it sounds like a stall warning on a cessna aeroplane -- enough to keep me grounded, lets just say.