The new Trade feature that merchants now default to, is what I was referring to. So, I talk to Aron, and if I double click on an item, it is instantly sold for gold. I have to toggle to Barter in order to put it back to the old way of doing things.
The old way, I think, avoids the people around you from accusing you of stealing.
what you call "new way" was the default at launch, I usually avoid spending any gold, I usually prefer the other way around so I am not sure how it works if you don't have enough and how the "not enough" is calculated since you need to have 30 charisma (with neutral approval) to buy / sell at the right price. maybe there is a problem with who is buying vs who initiated the talk or some values are not calculated properly... just speculating, it would need some testing, won't have time to do it before a day or two so feel free to test by yourself