Drat! my long-winded reply just vanished. That'll teach me!
I'm not in favour of "ordinary people" on WDYTYA?. It's the joy of poking around in the history of someone well-known, and seeing that there were ordinary roots, that makes it work.
A "Joe Soap" series would close it down. It'd be great fun for the person "being done", but boring as old socks for everyone else. A programme or an Open University course on researching might work, but that's a different matter. Most people in "ordinary" families get a bit stuck once they've worked back through census reords
Like everyone else, I'd really quite like someone with one of "my" names, in case there was a link, and looking on earlier replies, yes, Maggie Smith, John Nettles, and others would be great - I think! But I'd like to see others than actors - the Jeremy Paxman one was good, because most of us knew only a public face, in one role. First rate scientists, serious presenters, writers .... oh, dear, they're all too busy doing their real jobs.... but a Brian Cox, a Dar O'Brien, or similar may work well. And especially when they say "I know quite a bit about my father's side ... but not about mum's, and there's always been this tale about great aunt Nellie...." It's interesting too to see their "Family legends" debunked or made true, like the rest of us. (I did enjoy Sue Johnson's episode - but yes, it totally put me off the woman) I'm not so keen on the bits where someone's great grandfather was a baker ... so they bake a loaf.
BUT like most of the rest of us, I'm always interested when a new series is announced.
With "celebs" - I almost never know who the "Celebs" on things like seasonal University Challenge or Mastermind are, - but I think that's more down to my age group (never seen CBBC) than anything.
