Jameis Winston? Marcus Mariotta? These are 'upgrades'. They're both on the bench for a reason. Why do you replace a solid starting QB with someone else's back-up? The Rams have their own back-up they like - Wolford. See if he can earn the starting job and, if not, you've got a quality, inexpensive back-up.
As far as the 2nd round draft able players - are any that much better than Wolford, or better than Perkins who had some impressive college numbers and can also run and is bigger than Wolford.
The Rams have some pressing needs at other positions - ILB, C, WR, Edge - unless you're swinging for the fences with a Watson or Rogers - it would be a waste to throw away draft capital.
As far as Stafford - I'm torn. He does have talent but as bad as detroit has been - they've had some pretty good weapons over the years for him. His injury history and lack of success in getting to the post season and in the post season makes him less appealing to me. Though I will say Detroit was robbed of a playoff win against the Cowboys in one of the worst calls of modern playoff history.
