Yes MP10 is the most show accurate Prime released thus far but when Takara did MP22 Ultra Magnus and onward they seemed to do a shift to as much toon accuracy as possible with some people not liking the shift.

The MP10 Optimus does lack a few details like the grey coloring on his thighs and sides of his chest instead of white and unpainted horns on top of his chest. (Strangely Hasbro did this) even though I think only the movie showed primes horns colored. He also has the white band on truck mode which isn't present in the cartoon at all. They didn't collapse the wheels into his leg I remember reading there was a reason why they didn't do it can't remember it though.

If MP10 were to be released right now with Takara's current shift he would be much more toon accurate. Megatron's has a lot of detailing to the toon like the inner legs and his crotch front is actually toon accurate if you disregard the zig zag which is there so the panel can move (transformation probably) but the small squares on it are toon accurate. The top is his chest was probably unavoidable needing to put panels and moving parts somewhere it's better then non accurate kibble.

The MP cars were mostly designed before Takara's toon accuracy shift and they look better for it. Probably since they are based off real cars and the cartoon stripped a lot of detail. Which is why Wheeljack looks so different if they did him toon accurate his alt mode would be quite bland.