Dont believe all the horror stories posted here. (MIA has become the poster boy for bad-mouthing aiports, kinda like Cleveland for cities) often by beople who fly through the airport one a year.

Its not as bad as they make out to be.
Security in MIA can be a pain and is generally time of day specific (late afternoons/evening, Sat and Sun mornings are the worst)but I used the AC twice last weekend and was at my gate granted I flew from D within 8 minutes (yes I timed it)from the time I came out of the elevators.
Suggest you ask an AA rep to give you an idea as to how busy the airport might be at the time, but unless you are going to Sat E (gates E20 and up)you should be OK leaving the club 10/15 mins before boarding starts.

Look every airport has its busy period.
LAS can be pretty bad and LAX on Sunday last it took 30 mins just to clear Elite Security.
mike