My MT4G has never been rooted whatsoever, and I've experienced about 90% of the problems the OP has.
Dropped calls, locked screen/can't answer; dropped data & cell connection, text messages don't always send when you press 'send' (this CAN be very troublesome and create BIG problems with people) those messages may delay a day or two or not send at all, also happens if you are texting and the phone rings; and other various unpleasantries. I always figured it was a symptom of a bad/bum Android OS install- not hardware related. Horrid battery life/power management, too.
My wife has the same phone and has had a few of the same issues as mine, but not all of them.
Again, I've never rooted, or attempted to root my phone. I've never loaded betas or apps outside of Android Market. The apps I do have are very simple and fairly well-vetted.
Amazingly, most of my phone's problems have seemed to been taken care of by Android 2.3.4 Gingerbread. Thank God.
I still want an iPhone 5.