If it plays just like the regular GTA games, it is gonna be a mess in the form of an MMO. Imagine: Cars driving over people all the time, rocket launchers shooting wildly away, stuff like that.
Agreed, just something they would 'like' the idea of doing at some point in the future. There's not even any mention of multiplayer or MMO in the entire article.
Also, this has absolutely nothing to do with TESO.