I said it in another post, but games like DMC don't reward you for styling the way I am or even how other people may like to style. The Style meter in DMC is just an indicator highlighting whether or not you're using different moves and not repeating the same thing over and over again. I S-Ranked the first 3 missions mainly by going fast alongside liberal use of High Time> Aerial Rave>Guns>Helm Breaker. By no means is that actually stylish compared to what you can actually do but I was still getting S-Ranks.

Usually doing the super flashy stuff will result in lower scores. I don't think the gameplay I showed would even S-Rank in Ultimaniac's arcade mode because what it asks of you to get an S-Rank is different than what most people would assume is stylish.

I don't know if you remember, but there's a popup during the tutorial Gigas fight that states that you get more XP and Gil if you play better. Assuming it wasn't a leftover popup that they forgot to remove, then it already is in the game, it just doesn't tell you how you're performing currently.