That same "add more traction" argument for front shackle works just the opposite in my opinion, as the spring loads up against an obstacle it can toss you back off it.
I like SRS just because when climbing a ledge the tire moves rearward with a more natural motion.

It is all in how the SRS is set up, I build jeeps with SRS all the time, some more for trail, some more for street. There are trade offs for all these set ups.

SD