Really don't think it'll change the shows fortunes though - a clock isn't going to be enough to bring back the viewers they've lost.
Surely the programme was at its best when they filmed it close to being on air, be this the same day (if I'm right in saying so for the original 30 minute daily programmes), or within the same week.
As to get viewers back... maybe the only way is up. As in maximum prize that is. When it started it was the biggest jackpot to give away (even though Chris Evans gave it away on TFI Friday before Judith Keppell won Millionaire), in it's 12 year history it's never increased. Maybe a super millionaire idea could work. Especially if they introduced the time limit, and made it live!
I thoroughly enjoyed the recent series Million Pound Drop on Channel 4, and I believe that the live transmission gave it an extra dimension.
As Shafted was previously mentioned, how about the recent game shows that have disappeared. The Colour of Money - not a great format, maybe it would have worked better with questions beneath each colour rather than the stop the counter.
Pokerface had 2 series and worked well competing contestants against each other with the power of bluff, was there any reason given for this not being recommissioned?
Duel - I've got a couple of episodes of this that I watched the other week that I really enjoyed. I don't think that this got the backing that it deserved.