I personally don't mind the AGS, for the most part my truck appears to be well cooled. Like you I tow a trailer and that's where the problems start, guys have reported temps well over 250, in the neighborhood of 275 at times and that is not acceptable.
I'm probably going to go with an external oil cooler, leave everything from the factory "as is" and then the cooler would be thermostat controlled and only activate when temps start running above 240 or so.
I don't believe removing the shutters will do anything useful. The truck controls the temperature very well (for the most part) and it does its thing to get the temps up to operating as soon as possible, and then keeps it at that point. Only when towing do the temps seem to run away for a bit but at that point the shutters are already open wide, fans are on, but the truck can't shed the heat any faster. So I don't see how removing shutters (which are already open and "removed" from the equation) are going to help fix that problem. If they were remaining closed due to a bug, sure that might help, but they're already open, removing them won't make the truck cool down any quicker; we're just building more heat the truck can shed so we need bigger coolers or more of them. Using a thermostat so that the new coolers only activate when the temps are running out of control means that we won't interfere with the heating/cooling system when we don't need it and the truck can operate as designed for 99% of the time.