What if every year, each team was asked (forced) to present a design of what an unregulated F1 car would look like according to their designer/team. Like the Red Bull X1 prototype Newey did for GT5.
A few sketches and half an A4 of explanatory text. From every head designer.
Perhaps a deadline of just before the last GP.
These designs would be put up for a public vote. The design the public likes best would be considered the winner.
Maybe prize money, or 3 million $ goes to the charity of choice or even championship points, whatever.
As long as the prize would warrant a serious effort on the part of the teams. Maybe even championship points
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Think about it, every year the world of F1 would gain such a new, wider dimension, even if only from a technical interest, progression standpoint, let alone all other benefits.
And year on year the ultimate "what if" question, would be answered, AND kept up to date with advancements in technology as years go by.