With 3 or 4 limpers you want a very substantial raise.. You dont want AA in a multiway pot beccause with 3 people in the pot AA drops to about 60%, at the same time pot odds are correct for much weaker hands.
You are only 60% to win, but to win 3-1 on your money, for an expected return of 180%. With 4 callers, you are only 45% to win, at 4-1, also 180% return. With 1 caller, you are 85% to win 2-1, which is only 170% retrurn. So which one is really better?
All these answers, and the key phrase "bet-sizing" never comes up. Bet-sizing is the key to playing AA. You have to size your bet, for your position and your table, to get the amount of callers you want.
If you want to take a chance and go for a big pot, you want to size your bet to get 3-4 callers. You want to win a pot and go on, you want to size your bet to get 0-1 callers.
The other way to play it is to try and size your bet to get somebody to reraise, so you can come over the top. This is more likely to work when you are in early position.
If I am in first position, I will often min-raise. If the table is tight, this will still fold most people, and if it is a loose table, somebody will reraise and I can come over the top. And I can min-raise in first position with any hand I am willing to play, so I'm not giving away any info.
In late position, or on the blinds, a min-raise isn't going to fold anybody who is already in. So, if you have 2-3 callers, a min raise is good. If you have more, then you need to bet more.
5x the BB usually folds everybody, 4x folds everybody most of the time, 3x usually gets somebody to call, Negraneau's favorite 2.5x usually folds half the players.
So, the amount to raise varies by your position, stack sizes, and the nature of the table. But winning with AA is always about sizing your bet, based on those variables, to get the amount of callers you want.