I found that the first two problems you describe happened to me quite a bit in the beginning, but once Medtronic replaced my transmitter those problems went away. I think faulty transmitters are a bigger problem than Medtronic might believe.
As for the third scenario you mentioned, that sounds intentional. They don’t want to interfere with what you are in the process of doing. They don’t want the screen to be hijacked with data from your meter if you are in the middle of giving yourself a bolus. Sure, they can make window-shade notifications like smartphones have etc. but at the end of the day they make one pump for everyone, and they have to make sure that everyone from ages 10-95 can use the pump without confusion. Once you exit those screens and go back to the main screen the meter reading will show up.
There is no question that right now the 670 is overly cautious about making sure your CGM readings match your BG readings. It’s the first product on the market that can deliver insulin automatically and make decisions on your behalf. Both Medtronic and the FDA want to be absolutely certain that it’s not delivering too little or two much, and if it gets even the slightest whiff that something isn’t right it will ask you to check your BG. I do believe that future models will pull back on this significantly.