Especially if the war of the ring or other plot was on-going and you could participate as you pleased, potentially shifting the balance one way or the other.

That is actually a really cool idea if it can be done well! Not a new member of the Fellowship or anything too directly cheesy, but somehow get pulled into a quest to help at Helm's Deep and then Pelennor or something. Or you can get connected to help Sauron through quests in Harad or Rhûn. Likewise, it would be cool to potentially help revolutionary movements in Harad or Rhûn that oppose Sauron.

So much potential!