There is a thread like this on the autosport forum, and I thought it would be interesting to discuss it here.
Recent history indicates that F1 is not necessarily a good fit for manufacturers, with Mercedes being the one exception. Toyota, Honda, BMW, Jaguar, you name it, they did not succeed.
But in a perfect world, which brands or teams from other racing disciplines would you like to see in F1?
My first pick would be Ford, as works team or PU supplier. They are the only US team with an international racing pedigree and F1 history.
It would be good to have GM in F1, too, but I don't think it would make sense for any of their brands. Maybe Opel, but they have little to gain there.
VAG should have presence in F1, but I don't see that happening. Porsche would be a logical (or desirable) candidate, but I think the stakes are too high for them. They can't risk damage to their reputation if they are not competitive right away, and we have seen that success in F1 usually takes years.
I think BMW does belong in F1, but probably just as an PU supplier. It would make sense, as they have publicly committed to 'hybridizing' their entire vehicle lineup over the next seven years or so.
And yes, that goes for Toyota, too. But I'm afraid their first F1 endeavor has left them permanently averse to F1.