I have three M&Ps; the first one was a full size 45. It is a good gun, but keep it factory fresh every 5k rounds and it will run like a champ. The other two are 9s. None came with bad triggers although the two later pistols had gritty trigger pulls. Two hundred rounds was what it took to get rid of the grit. After a few hundred, you can further help smooth things out by removing and cleaning the firing pin safety plunger (or whatever its called), but that task also involves removing the rear sight.
My 45 has run over 8k rounds and a lot of dry fires. The striker broke at 7500, but I've never had a malfunction with 230 grain factory ammo, ball or HP. At around 6k, it started to have some feeding problems with 185 grain stuff, so it went back under warranty and got the recoil spring and some others replaced.
I do not recommend messing with the trigger on a duty or carry gun other than smoothing them out. A smooth trigger action won't open doors to create doubt that could get you into legal trouble like a lightened trigger might.
Also, M&P and 1911 triggers are apples and oranges in comparison, so get used to the M&P and accept it for what it is.