+1, especially when it comes to reducing the size of guilds, the current amount (100) is far too high for a game like PRO, where most guild slots end up being occupied by alt accounts.
Reducing it would also "kill" the top guilds that effortlessly work their way up the ladder again and again, as they wouldn't be able to solely rely on their active member count to get more points anymore.
Personally, I favour quality (in this case, skill) over quantity, and it's the opposite that is happening at the moment, which I think is a shame.
Reducing the number of players per guild would also incentivize smaller guilds to try to push again (it's currently almost impossible for them to overtake the top guilds, even if they tried their hardest).
I'm also down for guild wars, it is a very cool and engaging idea that would bring a breath of fresh air to the PvP aspect of the game. If they were to be implemented, it should be at the same time as a proper rework of guild island, imo.
Another idea that I think would benefit guilds would be the addition of guild missions/tasks, whether PvP or PvE (preferably both). This would encourage players to work collectively on tough objectives, which could give guild rating and/or bonuses upon completion. This would add a nice cooperative aspect to guilds, which I think PRO is sorely lacking at the moment. It would also be a good way for guilds to generate rating without "spamming" PvP matches (which I think is an issue).