On the former...
He was brilliant at taking the ball to the line, and making the right decision to pass the ball once there.
But at international level, A] The international gameplan he was playing was pretty much always designed for a different FH (OF), B] his first support player was Farrell at 12, who wouldn't be offering anything, C] there are fewer right options anyway, and D] if no good options presented themselves, he'd take it into contact, and get absolutely ragdolled (though often finding a way to maintain possession - gods alone know how) which => E] at international level his backrow were tasked with rucking over him if he took contact, rather than providing a good option to receive that pass - meaning he was down by 2 of the options he needed, which meant the defence wasn't stretched.
On the latter - I'm not sure I've seen him trying a full-on acceleration or sprint to judge, but with the various niggling lower limb injuries he's played through, I'd be amazed if he hadn't also lost some speed - but the criticisms way pre-dated that.