I feel aesthetic appearance is just art design. Like you and I could both be in an art class together, and we're both painting the same thing, but yours might look very different than mine, but that doesn't mean you and I painted something different, right? My feeling is saying one's "kelvin" and one's "prime" because of art style is like saying you believe when Nero (thanks @Jinn!) came back, some sort of space ripple went out both forwards and backwards and changed how everything in the universe looks, and I don't believe that for a moment. I mean things just look different, right? And Kelvin isn't simply "not the same as prime", I totally could be wrong, but I understand Kelvin means "a split timeline caused when Nero came back in time and he changes history, creating a parallel universe", so to be Kelvin you'd specifically have to be in his parallel universe, which looks exactly the same as prime aesthetically, just that in 2009+ our show creators are using different artistic style than in 1960s, right?