what exactly were the changes that caused unforeseen issues?

weren't changes for HF20 posted on github at least 9 months before?

what are the issues currently effecting users ranks?

RC costs are only an issue for very low SP accounts dont see how that's relevant for the rest.

these bonuses were promised before HF20

quote from your post prior to HF20 on the 18th of Sep

All Shadow Rank boosts will be given out today once full service of Steem is restored.

https://steemit.com/steem/@shadowbot/steem-outage-not-shadowbot