Damn, that's a seriously unpopular one!

But, consider this.

It wasn't so much Elijah by himself that made his Frodo great.

It was the chemistry and dynamic he had with other actors, especially Astin. The way they played off of each other made the movies great. It was synergy. Mind you, Astin killed it as Sam. Just a brilliant performance, and he could have carried anyone as Frodo the way Sam carried Frodo.

But the two of them? Possibly the most amazing duo performance I've ever seen. They made each other better, and the way they expressed the lines together was bloody art. I genuinely don't think there are many actors that could have paired up as well as they did.

Are there other actors that could have done a better Frodo in other ways? I wouldn't argue with anyone that said yes. There's certainly plenty that could have done as well (though Wood does bring a delicate vulnerability to the role that's hard to deny).

I've seen suggestions of alternative casting for every role, but I can't think of any for Frodo and Sam that would have been so magical.