not an expert in Omaha but my opinion is ..... all in preflop unless shortstacked and necessary is reDONKulas.
I personally only rarely raise PF . the flop is the only way to even remotely know where you stand in a hand .
this is the way I look at it , AA will definitely not win by itself and even a set very rarely wins in Omaha , I like hands with the chance to get high straight or nut flush .
AA with some other good cards is a good hand and all in preflop will probably get you heads up and give you a good chance to win but I don't do it period unless shortstacked .
but I'm not really someone to listen to , just giving my opinion
study the game a little more before you start that habit is all I'm suggesting