From my experience, the picture at the beginning has always been hit and miss. Some TLC is likely in order. That attraction runs about 12 hours a day, 365 days a year. That's over 4,000 hours per year, which does lead to some wear and tear.
More interestingly, Who should replace Judi Dench?
Benedict Cumberbatch would be truly awesome. A nod to Dr. Who, with Matt Smith, Tom Baker, David Tennant or Peter Capaldi would be great. Good arguments could be made for Derek Jacobi, Kenneth Branagh, Ming Na Win, Isabella Rosalini, Carrie Fischer (alas, not meant to be), Tilda Swinton, Allen Rickman (alas, also not meant to be) Benedict Wong, Glenn Close, Michael Gambon, Samual Jackson, Bill Nighy, and on and on and on.
Got to admit, Judi Dench has always been a bit school marmish to me. Personally, I think they should change it up ala Star Tours, with different narrators switching off during the day. Cumberbatch one time, Nighy the next, and Tilda Swinton the next. That will keep the guests coming back. Of course, the attraction is plenty popular even with the same narrator every time. No big need to change it up, I suppose, but it would still be great.