I don't really like this development. I think it cheapens the debates in the House of Commons where the party leaders clash weekly during Question Time. Also, every major government initiative is debated is Parliament. The government presents its agenda and the opposition parties critique the government and offer its alternatives. In the UK, Parliament is supreme and I fear that a televised debate will further reduce Parliament's relevance.
I am also not a fan of televised debates. I have watched American style televised debates since I became politically aware in my teens. Rarely are the debates edifying. The goal in an American debate is to avoid a campaign killing gaffe and deliver a glib and snappy put down to the opponent. Positions and issues are not clarified and the debates are not very informative.
My criticisms not withstanding, I do hope they show the debate on C-SPAN.