I think he would be tempted but he'd think it too dangerous to play himself, especially with how technology keeps improving and how everyone expects him to do so in some role. He might play another character though, especially if he practices twisting his voice before trying out. How about Methos as Darius? He could consider it a sign of respect.

I also have to wonder what part of Methos's adventures would make the kids cartoon, considering how most of history is not kid-friendly when studied in any detail. The only kids show I remember about history is Hysteria, which was mostly songs and catchy ways to remember history. What's a better way to capture kids' attentions that to tell them about the Vomitorium? And who needs to know the names of Henry VIII's wives when they can simply remember, "Divorced, beheaded, died. Divorced, beheaded, survived." Unfortunately, I was never any good at remembering history in any detail.