It is unlikely that anything so covertly political would be allowed in the run up to the General Election. The y have even postponed the next series of 'The Apprentice' because Alan Sugar is a Labour Luvvie.
The general voter apathy in this country is a problem. Part of the problem is that politics is so badly presented on our media. television is reasonably objective, but is presented in a very dull way, so Cowell could have a role in explaining things in a simpler, more popularist way. Our newspaper media is heavy biased one way or the other, and tend to preach to their readers rather than explain truthfully the issues.
The political parties will try to use the new media, internet and texting to reach the youth,but my guess is they will fail because they are very conservative institutions. Obama managed to do that in the States, but we lack the same vision.
If Cowell is able to pull something off without it being crass, then best of luck to him.