I think the reason why most agents work exclusively with buyers is because its easier, they know they can take an offer listed with a solid agent who would work with a client to see the merits of the offer and do the behind the scenes work to ensure it closes.
I've dealt with a lot of FSBO's, they have no clue what to do when the going gets tough and negotiations are getting intense. This leads to two things, no deal..where they get emotional and just stop negotiating...or a poor deal. A good agent should protect their clients from this by being a good negotiator. I'd like to see a seller, who thinks they know what they are doing, get in the ring with a Brad Lamb, Ellie Davis or Sylvia Morris...they are more likely to get whipped.
I know what your saying, the market is good, lots of buyers, therefore offers are easier to deal with. Thinking this can lead you to a false sense of security if you are a seller. From experience, I know the power of the one liners in agreements of purchase and sale. Once signed, the seller is bound, the buyer has conditional periods or irrevocable periods and can get out of a contract.
If the market dropped and a buyer refuses to close, the seller has three choices, find another buyer at a lower price, or sue the buyer to close or do both. The courts would more likely side with the party who acted professionally
Even agents, who are supposedly trained, are bad at closings and review contracts...This is why errors and omissions insurance exists, it would save the seller from tremendous liability/