I highly doubt a new WarZone will bring players back. EWH sets with worse stats than WH definitely won't.
We need Open World PvP with similar, better and/or different rewards than WZs (like other types of sets or something with different bonuses). 1v1 with rewards also might.
We need a different mechanic.
After max/min WH, there's pretty much no reason to play for.
^this. Personally, I'm not a fan of vertical scaling in the endgame because there is little to no replayability and motivation to keep playing once you achieved the top of the vertical scale. After achieving the top, you end up waiting for the next big update to the game which can get boring. I don't think its sound business plan actually. I'd prefer if bioware figures out that certain sandbox elements such as a functional world pvp, etc. has a lot of replayability factor requiring minimal updates which saves them money.