My core AR's haven't changed much in the last three years since I settled on what I like. My two most used guns have *shock* keymod rails, not new hotness rails. My oldest upper has a C4 which is going nowhere.

As far as the FF vs plastic handguards debate, I prefer a longer reach for comfort and recoil control.

One thing that happened in the last couple of years for me was a consolidation of handguns. Those I sold off were used to upgrade my reloading and other gear.