As it stand right now, every member of an alliance can earn up to 4150 AP per week, and in JP it's around 50,000 so around 10 times higher. The current limit we have kills the potential for new alliances almost entirely, as we draw closer to episode 6 content where the tree buff (20% attack to name one!) becomes more and more important, and is almost impossible for smaller/friends alliances. If you've made an alliance with friends, or prefer it small:
Just to raise the attack part of the tree to maximum a total of 295,000 points are required. This means one person trying to upgrade the alliance tree would need to spend 65 and a half weeks (~460 days) to upgrade one of several buffs. Or almost 10 years to max the tree entirely.
As a new player why would you join a smaller alliance when you'll have weak buffs, and miss out on triboosts, silver keys, and more every week from the AP shop and won't ever be able to catch up in a realistic time frame, when you could join an already established alliance from the start. This is frustrating all around, as with a higher point cap a group of 5-10 people will only need to spend a month or two (in theory) to start benefitting from an alliance instead of the current insane amount of time it'd take.
Punishing new players and returning players for making alliances is really unhealthy for the long term health of the game as well.