This is a concept I've actually wanted to see done... or perhaps do myself... for some time now. An elderly Sherlock Holmes living in retirement tending to his bees in Sussex. However, novelist Mitch Cullin beat me to the punch with his 2005 novel A SLIGHT TRICK OF THE MIND.
Which I just ordered a copy of.
I always envisioned John Neville, who had portrayed the great detective in one of my favorite Holmes films A STUDY IN TERROR playing an older Holmes. Sadly, John Neville who had been suffering from Alzheimer's disease passed away back in 2011.
However, I think the choice of Sir Ian McKellen as Sherlock Holmes is excellent!!
They even have Nicholas Rowe, who played the character in YOUNG SHERLOCK HOLMES, making a cameo appearance as a "Matinee Holmes". So I imagine he's portraying a very Basil Rathbone version of the character.
I'm looking forward to seeing the film. I imagine it will still be better than watching ELEMENTARY.