They didnt seem to think much of the torque arm because it has some compromises as well but it was better than a 4 link. You can arrange your three link set up for over steer or under steer through chassis roll.
This Is A Defender 300tdi My Good Friend Justo With A Front 3
3 link or 4 link for road racing. I seems your right about your observation about where shocks mount but i dont think it applies. One has 3 links or 4 if it uses a panhard and the other has 4 links or 5 with a panhard. In my experience if you are linking a framed truck it is easer to go with a 3 link. There are many different types of 3 and 4 link setups out there as well. All too often track bars are made out to be an enemy and thats just not the case. I recommend running the top link with a fair amount of anti squat built into the adjustment and a downhill angle of around 4 to 7 degrees.
Theres no better method to setting the roll center height and keeping an axle laterally constrained than a track bar period. Experienced crew chiefs use the three link set up as part of their set up package. 3 link rears are very cool and if executed correctly will perform even better than a triangulated 4 link. No three links are easer to layout and are more simple. Still the same old story 3 link if you want to do corners 4 link if you want to point it straight. Just saying 3 or 4 links does not describe the suspensions you are investigating well enough.
That is when the torque arms first started coming out but at the time all the road race cars used 3 links.