Rogers and Mannion's head movement is far different, Rogers intentionally does that type of stuff, Mannion seems to only do it once, when the ball is snapping. This entire preseason there has only been one neutral zone infraction called on the other team. It was Mannion at QB, so I'll credit him, but that's not nearly enough of a sample size to suggest that Mannion is better than Goff. There were neutral zone infractions last year when Goff was QB as well, but the sample size is simply not big enough for either QB to suggest one is better than the other at it.
Bradford was someone who was very good with the hard count and drawing players offside. Neither Goff or Mannion have shown they're good at it like Bradford did.
Ball placement can be a flaw, and your right it does depend on coverage, and the point is to give your receiver the best chance to catch and run with the ball. Mannion has no shown to be good at giving the receivers a chance to catch and run with the ball, in fact he's shown the opposite, and that's something that twitter guy correctly identified. To be fair, I didn't see Goff doing a very good job of this as well last year... Sometimes he was good, others he wasn't. He seems to be more consistent this year, but if I don't see a noticeable step up from last year, I'll be pretty disappointed. You can recognize a hot read and locating the mismatch without locking onto a receiver for the entire play, which is what Mannion says.
And here's the rub. Above you say that it's okay for Mannion to lock onto a reciever, in fact you say it's good because that's someone that "recognizes his hot read or recognizes the defense and locates the mismatch and attacks it"
But when Goff does it?
So which is it? Good or bad? The answer is bad, no matter who does it.
It's not the new "weak arm" stuff because that's very subjective. Hanging out receivers to dry is very easy to see. Are receivers getting freaking crushed by the defense more often when he's throwing? Yes. Are open receivers being missed while another receiver gets crushed from a hit? Yes. Are receivers needing to adjust and jump for balls exposing themselves more often when he's QB? Yes. Is that a problem in a coaches eyes? Yes. Is it something that can be fixed and coached? Yes.
That's fine and dandy, and I'd rather him throw too long so it's an incompletion than an interception, but it's still a poor throw. I don't think he's scaring defenses by overthrowing receivers though. Especially if they can know if he's going to throw deep or not based on who he's looking at.
Because there was another wide open receiver (87) who could have walked into the endzone.
Again, I have no issue with the throw or the pass other than the fact there's another wide open receiver for the TD, one that offers less of a chance of a incomplete pass or an interception. I wouldn't be upset if Goff made the throw, just like I'm not upset that Mannion made it. That doesn't mean there wasn't a better option on the field though.
That's literally the exact book on Mannion, that he gets rattled easily, can't handle pocket pressure, and struggles if you take away his first read. Seriously, look at the draft profile on Mannion
http://www.nfl.com/draft/2015/profiles/sean-mannion?id=2552576
Goff has shown the ability to sense pressure, step up in the pocket and deliver an accurate passes, to be fair to Mannion he has as well, but Goff has shown he can do it better and more often throughout his career, including college.
Then you're not watching the games and this entire debate is pointless. You're either intentionally ignoring things or not paying close enough attention.
He's also playing against second and third stringers. Frankly I'm not concerned with that, I'm concerned with Mannion's flaws as a QB, not about the level of competition. Playing with the 2's and the 3's against the 2's and the 3's only helps him overcome flaws such as locking onto receivers and making somewhat inaccurate throws that require the receiver to adjust for.
Goff was drafted in large part for his ability to move in the pocket to handle pressure and adversity, he's shown that trait all throughout his career. He struggled with it last year, but has looked much better this year. Both in practice and during preseason games.