At the moment on our server we have companies that all use the same set of highly geared and/or skilled core members in the war roster as well as companies that split to hold multiple territories but stagger the war window so that they can all be defended with exactly the same war roster day in day out. Effectively no matter where you go, you see the same setup.
If each player were able to only attend 1 war per day, then companies would not be able to split in order to use the same players to defend multiple war windows, and they would have to be more strategic in who to chose in order to defend which territories, either if they get attacked themselves, or if their allies call for help… you would not always see the same players in every war - where you put your stronger groups/players would be a major decision every time.
It would give more players the opportunity to get involved with wars, especially when the open world conflicts are pushed strongly on a given day. This will also promote open world pvp, because if you defend multiple territories, you would probably not want multiple wars on the same day… you would actively defend against the open world missions rather than just sit back and let them both run knowing you can run your one highly geared war roster against every single war that happens.
Having more people need to get involved wars means that more people have a need to and interest in gearing up, having 50 max geared people who no longer log in, save to just do all the wars on the server will no longer happen.
Thanks for reading and see you out there!