There probably is something. If the research has been done, I haven't heard of it. We will probably have much better guidelines some day.
It is similar to drafting players at 17-18 YO and hoping you can accurately pick the best ones and know how they will develop over the next 4-5 years. That is the upward side of the bell curve. We are talking about the downward side. They are somewhat similarly difficult to predict. I think the downside is a little more predictable though. The effects of aging hit all of us. We have lots of data.
The Jagrs seem strange because he and Gordie Howe are the only 2.
They don't just seem strange, they are strange.