Are we sure there will be a human narrator though? I mean I guess if the refurb is not as extensive as originally planned, then they’ll have to keep the narrator structure, but otherwise I’m not sure the narrator role will be the same.
Idris Elba would actually be a good choice in my opinion.
Cumberbatch and Patrick Stewart are both great suggestions. I'd also really enjoy Ian McKellan, and bringing back Jeremy Irons would be just fine.
In the non-British category, I actually do not want Morgan Freeman -- not because I don't enjoy his voice, but because I just don't think it fits the attraction for some nebulous reason. I think Laurence Fishburne or Keith David could work.