See:
http://www.ago.state.ma.us/sp.cfm?pageid=1170
Specifically, see: "* Does the handgun have built-in childproofing protection (Section 16.05(2))? If you are unsure whether the handgun meets the Attorney General's childproofing requirements, you can ask the manufacturer. A handgun will meet these childproofing requirements if it contains a mechanism that effectively precludes an average five year-old child from operating the handgun when it is ready to fire, including but not limited to: a trigger resistance of at least a ten-pound pull; a firing mechanism that makes it so that an average five year-old child's hands are too small to operate the handgun; a design where the handgun requires a series of multiple motions in order to fire the handgun; and/or a hammer deactivation device."
The M&P does not have a decocker ("hammer deactivation device") or a manual safety ("requires a series of multiple motions"). Therefore, if the trigger pull is less than 10 lbs, I believe that the AG would rule it to be non-compliant.
2) Standard capacity (>10) versus crippled capacity (10 or less). I don't remember what the standard capacity was of the full-size .40S&W that I handled -- something like 15 rounds. Since these magazines were constructed well after 1994, they are of post-ban construction, so the standard capacity mags are illegal in MA (except for LEO).
So, are you implying that the AG now does not need to do anything for a pistol to be MA compliant?
It is my understanding that the AG normally doesn't do anything in this process. The AG doesn't issue "approvals". The AG doesn't distribute a list of approved guns. The AG's office won't tell a manufacturer that their gun meets or does not meet the AG's regulations. What the AG does is threaten lawsuits if someone sells a gun that he rules is not compliant.
I believe, therefore, that the only thing holding up the sale of M&P in MA, now that they're on the EOPS list, is S&W.
I haven't been close to this process -- just second and third hand information. Perhaps Scrivener can comment, as he has had more experience in this area than I.