People act like there couldn't be a "NEW" group just like the Wardens.
Remember, the Wardens had to start somewhere.. someone was the FIRST, so its not like you couldn't figure out their "trick" and do it again if a new group needed to be formed.
The way I see it, the Wardens are no different then the Inquisition. It was a group of people who got together to fight the first blight any way they could; and just like the inquistion, once their enemy is "gone" the mission will twist and change.. the Wardens of today are a lot different from the Wardens of "then".
If they make a DA:4.. I fully expect them to set it in the "Future" like 100+ years has gone by since the formation of the Inquisition... and I fully expect it to be a completely different beast.