I think it will sound epic regardless of the engine.

For reference, BMW is currently finishing up the development and testing of their 1.6L turbocharged 4 cylinder with direct injection. It's thought that BMW could potentially become an engine supplier one more (like the 1980's). I'm sure Renault would prefer smaller displacement, 4 cylinder engines given the majority of their line-up are powered by that type of engine.

To be honest, F1 is fairly irrelevant right now compared to many other series(GT in particular given it's close relation to road spec cars) I think this will be a shot in the arm for what's supposed to be the pinnacle of motorsport.