Like everyone else, I have watched a few of Stafford's game with the Lions. One highlight reel; the others just at random. I confess that I didn't know much about him; but if you ever listen to Aikman (who I think is second only to John Madden), he is simply ga-ga over Stafford. But after watching a few of his games (thank you NFL Gamepass for the condensed versions!)..... my goodness this guy is good.
Why he didn't find a way out of Detroit 4 or 5 years ago I don't know. Talk about trying to put lipstick on a pig. The Lions have been a mess for decades all the while having the single hardest thing to get: a Superbowl caliber QB. They can occasionally get a good player here and there (Megatron, Stafford), but a good team? A good O and D at the same time? Just didn't ever seem to come together. So it was just constant change, with more or less the same results.
But... the NFL guys that have followed the game for years, or played the game for years, say that Stafford is elite. Archie Manning said that Stafford has the best arm talent of any QB, ever, at his famous Manning QB Camp.
The Rams have perhaps the most complete team in the NFC, by adding Stafford. It hurt to lose Akers. But if Akers is a 8 of 10, Henderson is no worse than a 7. So it's not like the bottom dropped out of the running game. If they don't win the West and the Conference, it won't be because they don't have the QB. They have an almost embarrassment of incredible skill players on offense, and a D that was #1 last year, and is going to certainly be good again this year.
Now they have a QB that has no playbook limits. If you can draw it up, he can run it. The Rams QB position has gone from a Lexus to a Lamborghini. Goff was not a bad QB; but Stafford is a VERY good one that can do things that few other QBs can.