It makes for an interesting debate, for sure. I tend to think that maybe it shouldn't be tied to age, but if you've played professionally in another country, you shouldn't be eligible.
I don't think that's right. If somebody played in the IL or PCL, that's fine... but if they played in the Mexican League it's not? What about some league in the Netherlands or Australia? Does anybody think Korea's league is as competitive as the IL or PCL?
I'm guessing what you really mean is the Japanese leagues. I think the only reason people would consider that is because of what Ichiro did. Before he did it, it was a big open question about how he'd do over here. It's only in retrospect that we can see that he was better than everybody.
IMO, if we want to maintain the belief that MLB is the highest level, that means permitting all newcomers to be eligible for ROY. Either that or treat Japan like an MLB equivalent. I don't think you can have it both ways.