Wouldn't he need to rewrite stuff, though, if new features get put in that obviously have ties with the lore? (such as the pylons)
Well... yes and no. For one thing, the pylons really don't affect the lore. Most of the lore is regarding past events and world history, not current events, and the pylons are a current event. That said, current events get tied back into world history in various ways. And the world history and general backstory lore that Keith has come up with is really robust, I have to say -- and it has the same sort of fudge-room that AI War's lore does. In a world that is broken, filled with factions, and filled with magic AND technology, there's not a whole lot that one can't make fit into the existing lore.