I am sure he will take his lumps and have some bad plays/games as he learns to play QB day in and day out against starting opposing defenses who have game planned for his deficiencies. The key will be if he can develop enough as a passer to be a valuable NFL QB before he no longer has 4.4 speed.
Even though a somewhat slower Hill is still really fast by most measures, it is not quite the same. Most RBs and many CBs are done by 30 yrs old, because they lose a step. Everyone else on the field has not lost a step because, if they did, they were replaced by someone younger. Also injuries, can pile up when you are tackled that many times in a game every year.
This is roughly when Steve Young transitioned his game and elongated his career to become a better passer and run less. This will happen to Hill in the next couple of years, no one escapes it. Will he have other tools by then to continue to play at an NFL level? I hope so.