these seem like very different (on a conceptual level) tasks to me and not necessarily type related. and i do not think they are inversely related to one another.
for instance, i am very good at short-term rote memorization, but that says nothing about whether i understand the concept. to understand a concept i must start with an overview, so i can understand where to "fit" those details in. i don't understand how to string the details together unless i have the big picture... they all just seem a messy muddle of irrelevant facts to me otherwise. if i have the big picture, i can fit the details in and keep the memory - otherwise, the rote peaces out after a short while.
i do not personally think that there is a connection between N = conceptual and S = rote. i think Ns, especially doms, tend to need to start and end with the conceptual, and Ss would prefer to start and end with "world units" - ie pieces of reality. but that does not correspond to big picture vs rote detail - i know a Se dom friend of mine who is a big picture thinker because she tends to see things in "environments", much like i do (though hers are more temporal, and linked outside of time via Ni, while mine are more timeless and linked within time via Si).
thus i think the difference between N and S is more about theory vs reality as opposed to concepts vs rote.
so essentially as far as i understand it is like this:
Ne user - focus on big conceptual picture, made up of Si world-pieces
Se user - focus on big environmental picture, linked via Ni connection
Ni user - focus on series of archetypes, made up of Se instances
Si user - focus on series of world-pieces, linked via Ne connection
and we are all best at our personal focus. but that does not necessarily have anything to do with how good we are at rote memorization. i do think Si and Ti types have the most facility with taking a set of details and making use of them, since they are experts in piecing small units together.