I like this idea, but i dont like that stone wall should be used only as small fence.
It should be stronger than palisade, and i think no one will ask why.
Another point why i would like to stone wall be implemented is because they fit much better than existing brick walls. Just because brick walls (that look like those we have in game now) appeared somewhere around XIV-XV centuries and it looks like someone from future made a time machine, came to our time and taught all secret of wall building.
What we need:

What we have:

Stone walls should require large amounts of stones (500-600 per starting cornerpost? 100-150 per segment) just because stone is unlimited and easy-gained resource if you have at least one large rock near your base. Then maybe it should require glue or clay as cement material. And maybe one bar of any metal per cornerpost (or maybe iron/bronze only).
Dont blame me, just expressed my opinion.