Martin Freeman would have been a much better Frodo. Elijah isn’t even in the top 100 list of actors that I would cast as Frodo.
The LOTR movies succeeded despite him.
Don’t get me wrong, I like Elijah. I just feel that he was miscast in those films.
Martin Freeman wasn’t a good Bilbo, would have been even worse as Frodo, and a disgrace as Arthur Dent. He was good in Fargo though. And plays a good Watson.
However Martin Sheen would have been magnificent. Watch him in Good Omens - Bilbo to a tea!
I quite liked him as Arthur Dent.
Fyi you’re thinking of Michael Sheen, not Martin Sheen. I agree though, Michael Sheen would have probably been amazing as Bilbo