Super disappointing results. Might as well have not bothered at all.
If you looked at the threads where they asked... "you" basically didn't. There are 50,000 people (at least) and there were less than 100 total responses to the query.
Less than .2% "bothered" it's not overly shocking that the results reflect the response. No one to blame but yourself.
Leave every AH stack size the same but allow a personal opt-in in the Config menu to stack your inventory items to 99.
This was what I recommended. Allow it to stack to 99 but don't change the AH or allow the option to sell 99 or 12. Would've been absolutely perfect.