Technically, this mechanic was in early GW2 beta, except it wasn’t a commander tag that you needed to have, it was a mere mesmer portal entre. The distance between two portals was NOT restricted on map.
The portal could be used by players 40 times which was later nerfed to the now 20? Correct me if I’m wrong on the player portal cap, it’s been awhile.
The portal entre distance was later changed during the GW2 beta for many of the same reasons stated in above posts.
For reference: Team Legacy podcasts and youtube vids brought this to a lot of peoples attention during the early GW2 betas and how problematic it could be for the WvW game.