Having a player cap on Alliances will probably need to happen. Likely a number based on total ship player capacity and not actual player count.
As the most ships I've seen on a server is 5 or 6, the servers don't seem that big in terms of player count. So it would likely have to be limited to 8 players per Alliance based on Ship Max Crew. 2 Galleons, 2 Brigantines and a Sloop, 4 Sloops, Etc.
This observation is based on hearing a story from someone I usually play with on how an entire server Allied together on Saturday to farm Cursed Sails ships continuously. I'm good with Alliances, but a server wide Alliance that removes any in-game threat from both PvE and PvP seems broken to me.
