I would leave the short connection. As already mentioned, with (or even without Global Entry) you should be through immigration in minutes. Your biggest problems will be the walk to immigration (~15 minutes if BA gets it's usual gate at the end of E) and then waiting for luggage (if BA honored priority bag tags, this wouldn't be an issue. But since they're hit or miss, this could be a problem. I also have GE and have waited anywhere from 15 to 45 minutes for checked luggage with BA in MIA). Baggage re-check should be fine. And then the final issue could be re-clearing security. Half the time I've connected through MIA to MCO, the pre-check lane next to AA's baggage re-check has been closed. However, at this point unless the lines are really long, it's still easier to wait than to try to go upstairs and use regular departure security. Then find your gate which could be up to a ten minute walk though you can also use the tram.

The only thing you're almost definitely giving up on this short connection is a chance to use the MIA Flagship lounge at D30 which is probably the best in the system. Great showers, nice buffet, Flagship First dining if you flew from LHR to MIA in first (not sure if you are or not from post 24), good self-serve bar, etc. but if you do miss your connection, head back there. The other thing is that, depending on what time of year you are traveling, flight delays from thunderstorms get worse as the day goes on. so your 16:43 flight could be late. And later flights than that will probably be even worse.