The lack of effort to leverage the N3DS spec bump is extremely disappointing. Basically the only way Pokemon Sun/Moon benefits is from faster loading and not having to boot the system into low-memory mode (a la Smash 4) when played on OG 3DS. They could have pushed demand for N3DS by having PSS as a N3DS-exclusive feature in Sun/Moon.
Frame rate is much better on the N3DS when it comes to Pokemon. I played on my old 3DS until the new arrived and could immediately tell the difference.