I have heard this Idea posted many many times... I have agreeded with it each time... I think it is a great idea, that for some reason gets overlooked for other things.....
However, I'm going to suggest one alteration to the thought... Right now, my Casters don't bother with Teleport/Greater Teleport spells, as they are exactly like scrolls. I would suggest that the spells are the only things you can add locations to, and scrolls/items remain the same, as scrolls and items would be much more limited anyways.... since most places are easily enough accessed from the market, Teleporting from meridia to the market to get to Gianthold for a Reaver, easy enough for my fighter with Royal Guards Mask, but my caster should with the spell be able to do better. (not talking GT).
Not sure I'm being clear, hopefully you understand what I mean.