It's largely a big sandbox, as they call it in the gaming world, they'll have plenty of room to basically make up their own stories - and I imagine they'll make enough of an effort to keep it broadly within the limited parameters that exist, so as to keep the LotR feel.
That's probably a more promising starting position than the WoT show team had, having to compress such a long and detailed series into far fewer seasons and wanting to put their own stamp on it in the process.