Well, I just posted the "before and after" pictures so, I guess it's on the web.
The short version is I spend far too much time on this site. You're not the first to complain about the reset and S&W has heard this complaint. They've made the newer slide stop to address it.
The little protrusion pushes on the trigger bar which makes for a stronger reset. It works and I've upgraded my M&Ps to this new style. Here's a short video I made on how the trigger in the M&P works:
https://www.youtube.com/watch?v=5_RoDAOQGnQ