I want PGR5 to have lots of bokeh and colour. Gimme.
The lack of soul has a lot to do with the environments I think. Forza and T10 are really focused around realism and striving for the most realistic shaders, etc. While I don't think that PGR will be super stylized next gen, and will certainly move things into being more realistic too, there's a certain dash of flavor the aesthetics had that give it that feeling of soul. The colour saturation was always a tinge up from competitors and sims, and they were never really afraid to use bright colours either. It just made the arcadiness look that much more fun and inviting.
The environments in particular had this sort of beauty and art to them, and though understandably a sim racer doesn't care for environments much when they've got to put resources elsewhere first and foremost, even when you look at the NYC tracks it just feels drab. They remedied a bit of this with 4 but doing cities is a whole other deal. Having the right environmental artists who can convey the right vision is key for PGR5.
God, even just thinking about how they'll change PGR5 to keep it fresh makes me consider so many possibilities. Will they remove guard rails and the international professional racing aspect to make it take a more street-level competition? Will they continue the international series kind of favour? Will they take the franchise to drastic new places like fantasy worlds a-la PGR4's trailer and the Rare concept art? Will they make it an open world experience in London/elsewhere as possibly the biggest modeled individual city in a racing game? Will they focus on a few, big cities or several, relatively more limited ones?
There are so many possibilities, but they don't have to be limited to locations or that framework, it could be in gameplay too, but they're going to need a way to justify this alongside next gen to gamers like PGR3 did with GothamTV, track maker and all that, and I don't think anything is off the table considering the state of the franchise.