The first actor who came to mind was Chris Hemsworth—a muscular guy, not too old, with dark hair, and has some experience with comedy. Granted, the "comedy" aspect is unnecessary and relates more to my personal headcanons. That said, we do know he had a rather Dwarvish disposition, and Dúrin's folk are known to be occasionally bumbling yet noble. If it were possible to make a character ancient yet occasionally exhibiting the sort of humor
Gimli does in
The Lord of the Rings or even
Thorin and Company do in
The Hobbit I would be fine with that (although we must be able to take
Celebrimbor as a serious and tragic character when necessary.
That said, about Charles Edwards, I didn't mind his age
overmuch. Yes, it was a bit disappointing, and it would have been worse, I think, if they had kept his dynamic with
Galadriel intact, which I wish they had done. So yes, I think he should be younger, but the reason I think that is so important is because Galadriel should be older than him when she argues with him about trusting
Annatar, and that was entirely cut from the show. However, as it is, Edwards still captured the rather hubristic character in the book, in my opinion. So, his age bothered me more than Peter Jackson's
Théoden or maybe even Thorin, but less than the age of Peter Jackson's
Pippin. My biggest gripe is that we spent so little time with him, and I felt mildly shortchanged that, when they could have adapted his friendship with Narvi, they made up a friendship between
Elrond and Dúrin IV. Celebrimbor is my favorite member of the
House of Fëanor and possibly my favorite
Elf in the
Second Age, so I was disappointed with how little we got.