I agree that age discrepancy and vulnerability are relevant factors in such situations.
But I feel much more strongly about protecting young children than I do about the ages of sexual experimentation.
At some point these things are yucky but ought to be none of my (or a lawyer's or a newspaper's) business.
And I am very much against applying today's censorious model to behaviours in previous generations. As a teenager, I don't remember thinking it was an abhorrent idea for me to have sex with, say, a Hollywood sex symbol. In fact, rather the opposite. Sadly for my youthful self, it never came anywhere close to happening! But I was sexually active at that age (15 or 16) with members of the opposite sex (admittedly of roughly my age) and don't feel bad about it.
If I apply that standard to my youthful self, why would I be especially bothered by what Pete Rose did 47 years ago, assuming it was consensual and the culture was more permissive? It sounds like he fulfilled a teenage girl's fantasy. Was it obvious she was under age? Who knows? Statutory "rape" is consensual sex. It is just that the younger person is considered incapable of fully considering their decision. Yucky, perhaps. But something to worry about 50 years later? Not in my book.
For me, the fact that 21st century attorneys are chasing 50 year old cases of little importance is more scary. I am disgusted by the greedy and excessively litigious culture of today. Everyone is after everyone else's money, if they can get some of it. And the big winners in such a society are the greediest, most vengeful people and the vilest attorneys.