I like most of what you have changed. I will say I actually enjoy the Fire Frenzy on the Dreadnought.
Also Obliterator I like having more than 1. But maybe Iron Warriors could have Basilisk (same stats as Imperial Guard).
Daemon Prince for Khorne should have a either furious charge or NULLIFY for the psychic. This is because of the points and since the Daemon is a psych but Khorne is not.