I dunno if Quinn just had bad injury luck or is injury prone. 3 season really isn't enough of a sample size.
I can ignore his first season since he didn't have a full on supporting cast. Texas won a lot of games against tough competition over his next 2 seasons, but the deficiencies were obvious.
What I saw was that Sark worked to correct some form issues in preseason. When he had those habits ingrained, his motion was better, he saw the field, and trusted himself to make correct reads. The ball would get out on time and usually very accurately. Then, at some point early on, he'd get hurt and miss several games. No biggie. However, when he returned, he seemed to have forgotten all those "attention to detail" things Sark worked on. He'd go back to sloppy arm and body mechanics, throwing off his back foot, and double-checking his coverages - which mean the ball was out late. The accuracy would likewise fall off past 15 yards.
He doesn't have any real built-in limitations. When healthy, he can use mechanics to attack every part of the field. The NFL won't expect him to run out of trouble regularly, so that part won't matter. If the light comes on and stays on, he could be exactly the type of ball distributing QB that Miami needs (once they get tired of Tua not quite managing to get it). That could likely coincide with his 2nd contract negotiation, so we'll see.