A teleportation system would have immeasurable value in the realms for both commerce and warfare.
I disagree ...
Since its usable only for sentient beings, and you cant use it with animals, or war machines ... all you get is a potentialy faster transportation for infantry, wich is useless by its own for any siege.
Yes, you would get reinforcements much faster, that i would agree ... but so will your oponent, so in the end the scales are still in ballance.
Also we are talking here about world, where single archmage can create fireball that will destroy whole regiments ...
I think warfare is working based on a little bit different rules here.
The wilderness would be overrun with interested nations and parties trying to chip the portals off the rock and use them for their own benefit.
Unless they allready know that this portals are simply manifesting on such places, and ist tied to them physicaly, so they cannod be "chiped off and moved" ...
Wich i would presume they allready noticed, since this magic is there obviously for some time allready.
The Zhents are already there, how did they overlook this prospect of the century?
Did they tho?
I dont see much reasons to believe that its just a coincidence that one of their hideouts was made just next to portal ... nor see much reasons to believe that they bringed everything they had stacked there by the ladder they have there.
Red Wizards would want them, Harpers would try to make sure any wrong faction doesn't get them..
Sory, i dont know this factions ...
But if you mean by it that factions related to some portals should have guards there, i agree.
Drow and Duergar would use them to make surface raids for slaves.
Instant dazzling with daylight, instead of slowly getting used to it ... it sounds absolutely great, I'm sure every Drow or Duegar can't wait to do it again.
Goblins would use them for hit and runs between the fort and the grove.
If they even know where this grove is ... or that portal (since as you surely noticed, you can transport only to portals wich exact location you know) ... yes.
But if you listen closely, they were talking all the time about the fact that no one knows location of the grove.
