Fist of Fire would still be the only one used, as it would provide more uptime than the other two.
Improving potencies back to 3.0 just basically puts Fist of Fire on everything.
Riddle of Fire's change is a net gain, fairly large, especially with pre-4.0 Forbidden Chakra
Riddle of Earth interacting with Tornado Kick instead of Riddle of Wind is a bit confusing.