While a QB really selling a handoff doesn't hurt, defenses are reading their keys to determine run/pass. For the front 7, they're typically keying on a certain lineman or on a back, so that's where effective play action is sold. My guess is that comparing Carolina's OL vs other OLs on good play-action could be just as interesting as comparing QBs.
Per PFF, Norwell and Turner finished the season as the 16th and 23rd best guards in the NFL while Remmers was the top-rated tackle for several weeks. While not a definitive authority, those metrics give a good sense of performance and saying the line sucks outside of Kalil is incorrect.
4:30 GMT would make it 8:30 PDT, so not really much better, and the NFL specifically moved the games earlier in London's day to boost attendance. The games used to be played late so they would air at usual US times, I think as recently as 2013.
i'm not sure if this is in support or condemnation of Gettleman's strategy, but someone saying that this team has less talent and/or is in worse shape than before he got here in 2012 would be incorrect. I can't remember the last time a Panthers team had this much depth across the board.