I heard Whitmarsh say that and thought it was a crap idea. Mandating things is not the solution. A broader range of compounds and more choice of compounds, a la the 80's, and the ability to cross-match them (for those of you old enough, A compounds on the rear, B on the left and C on the right was a good Alain Prost set-up, if I recall) would make it much more interesting. Mandatory anything is against the idea of racing and ruins the chances of different strategies.