I rode a legacy (wide version of SL) during my first two seasons back after a 10 year break in 2006/7 during which I went from barely handling a difficult blue to shredding double-blacks and hitting most park features. Since then, I've ridden a friend's rome agent and started riding a capita sierrascope in 2009. Admittedly, I haven't ridden a proto....but I know it's rated as an all mountain freestyle board with more flex than something like the SL....similar to the agent and the sierrascope IMO. All that to say, here are my thoughts on your two criticisms:
- Given my experience with the directional twin legacy, I feel like the the benefit of something closer to a true twin is definitely worthwhile....particularly while learning to be better at riding switch.
- You do admit there *is* a difference in flex....albeit small. While I can't comment on the proto specifically, I would say the difference in flex between my legacy and the other boards I've ridden is also relatively small....and it definitely made a pretty big difference for me. I even went back to riding my old legacy for a couple of days this season just to confirm my suspicions about this.
Nowhere did I acknowledge that there is a difference in flex between the Proto and the SL. Now, virtually no two board models have an identical flex, but the SL and Proto are so close/identical that the difference, if there is one, is imperceptible to most people - and certainly to a beginner rider. There most certainly is no difference in the "kind of s[t]iffness" between the two boards. Incidentally, NS rates them the same for flex
Also, although very slightly directional, the SL is still a twin. For riding switch the difference is again imperceptible to virtually everybody and certainly a beginner - if you cannot ride switch on an SL without issues, you cannot ride switch, period.