because players hate pacts, not to mention most end up with one of the two parties end up backstabbing the other.
You cant limit how many players you can play with, same as you cant limit how much gold the players can spend ... it is that simple.
my point of ideal size, is that no matter what cap it is, best alliances always are 60~80 player - that is the only way to keep it without a pact and most important, you can keep replacing the players that leave the world for different reasons.
Whom of us wouldnt like to go commandos squad with 20 player and kick everyone around ??? but what happens when 5 players needs to leave ? what happens when real life kicks in ? what happens when those 20 player face 100 huge alliance pacted with each other ?
about the rim thingy, mate everyone go in the center of the core - you guys went to 55|65 border after 3 days world started only coz it is too damn slow in recruiting, do not let stats fool you and sorry to break it to you but that is rim by everyone else's book, if u want to pretend that your alliance started straight in the core and are fighting the big alliances (fighting what 1 ally of top 15 ?) ... then it is not exactly my business or my concern and good luck in fighting the big ghost that doesnt exist
on a side note, I have been playing this game for 5 years. I made some great friends here, so when someone of them comes and ask me for invitation, sorry but I aint telling him the stupid cap doesnt let me