With the old system, if they left a negative they knew they would get a negative and after a few negatives they would be suspended
Buyers have rarely if ever been suspended for having negs even huge piles of them.
The problem with the old system was just as you said, buyers were hesitant to leave negs for fear of receiving one in return. I suppose you might be one who thinks that no buyer can ever have proper justification for leaving a neg or that no seller would ever neg a buyer without reasonable justification.
For every idiot buyer there are at least the same number of idiot sellers. It's shown every day by the drivel posted on some of the eBay boards (even this one on occasion).
I'm all for giving buyers as much protection as possible, sellers can look after themselves.

"What else could I do? I had no trade so I became a peddler" - Lazarus Greenberg 1915
- answering Trolls is voluntary, my policy is not to participate.

"What else could I do? I had no trade so I became a peddler" - Lazarus Greenberg 1915
- answering Trolls is voluntary, my policy is not to participate.