I think it is highly interesting, and I like it, but I am not seeing eye to eye with you in regards to TC.

Your own fluff states that the world existed before the spell, and then some wizard invented it which changed the world.

This creates a problem in that I see no reason that some other Wizard out there decides that he wants to end the threat of a teleport invasion and research/invent an anti-teleport spell that can be used to protect vast stretches of area.

If TC was invented, that means other counter-spells of similar power could be invented*(naturally that doesn't mean they have, but if a PC or a DM using this setting decided too, they could totally do it.)


*Isn't there some rules in the DMG or something about inventing new spells for a niche that doesn't have any?