I agree, there are too much replays of the start. They should do it like in Moto GP : show the replay of the start when nothing is happening on the track, even if they have to show it during the second half of the race.
Splitscreen is also a great idea : it could also be used to increase the drama (for example if they are showing a pitstop on one screen, and another driver trying to get the undercut on the other). Besides, now a lot of people have a widescreen TV : that should help.
But I think we could be quite patient expecting changes from an organisation who introduced HD coverage quite late.