AGHADOWEY.....
From your comments here, I am inferring that some Rootschatters are diligently researching possible celebrities to be invited for filming, if Rootschatters can uncover a story worth showing?
And that the WDYTYA team including "researchers" then construct an episode from the information that Rootschatters have provided?
How intensely frustrating then, to find key pieces which have been provided, are not used or only tell half the story! 
Dont tell me that people on Roots are doing the work of the Researchers... for goodness sake. !!!! Well if so surely they could find someone worthy of an hours long programme.
I mean who the heck is Fearne Cotton!!!!!!!!!!!! and Ruby Wax........ etc.... its about time Someone who had been around for a reasonable amount of time and had made an impression on more than one particular area ...
It (to me maybe only) is becoming a case of going through whats left... So far this series only ONE was excellent and maybe one or two others had interest.
This is of course just an old ladies opinion... NEEDS more 'grit' No more Eastenders or Kids show people for me...
Judi Dench please ( have they done her yet) ...
https://www.youtube.com/watch?v=rHZtHlqdemMMickey Mouse, would be better than Emma Willis ('Who is she')
sorry...

xin