Yes, buyers do have rights...but I'm not sure they are the kind of rights you are referring to. You have the right to inspect the property for defects, mold, pest infestation and the like. This gives you the legal right to back out of the contract should the seller (or the sellers lien holders) accept your offer.
The problem with short sales is that everybody thinks that they can get a killer deal and save a bunch of money. In truth, you can but there are conditions. Short sales are cheap for a reason; they typically take much longer than an ordinary sale and the condition of the property can vary wildly. For the average home buyer, short sales are not the way to go. You need to able to wait the extended period that short sales require; you need to have closing costs saved up in addition to your down payment because most banks won't pay for any closing cost help; you need to have some cash set aside for repairs should the property require it and you need to be able to close quickly once the approval is granted.
If you figure 3.5% for a minimum down payment (on an FHA loan ), 3-4% for closing costs and prepaids and $5-10k for paint, carpet and maybe some appliances..that's 6.5 to 8% of the purchase price (up to $16,000 on a $200k house) PLUS $5-10k for possible repairs/upgrades.
On the other hand, if you get a good deal on a spec home from a builder where they'll pay most of your closing costs on the same $200k house you'll need about $7-9k to get into it and it'll be brand new. You might get a better value in the long run form the short sale, but..like I said...there's still a price to pay.
Something for nothing is not real in any world, and while you can get a good deal in todays market -a better deal than in a long time --you have to understand what you are working with.
As for your original question, it's hard to really tell what was going on there. Could someone have taken advantage of you? Possibly. Is there anything you could have really done about it? It depends. Were you promised anything contractually that wasn't delivered? Did you suffer any monetary damages specifically related to a failure to perform on behalf of the contracting party? Probably not. Did you have expectations that weren't met? Absolutely. Were things handled in the best way be the agent you were dealing with? By the sellers agent? Probably not. With so many people involved in the transaction -you, your agent, the seller, his agent, the primary lien holder, possibly a secondary lien holder, maybe a home owners association attorney, the mortgage insurance company, a title agent, you get the idea - the possibility of something going wrong or somebody not getting their expectations met is great indeed. The real problem is that this whole process is so complicated and so few people are really good at it and there are so many more shortsales now than before that the whole thing is out of whack and will be until it catches up with itself. And...as soon as it does, then we'll be on the tail end of it and things will go back to normal and shortsales will become the exception rather than the rule just like they always were before.
What you didn't say was whether you had your own agent or if you were using the homeowner as your agent. If so, well...that was a mistake. Anytime you buy Real Estate you should use your own Realtor. Not to would be foolish. The seller almost always pays for it and even if they didn't it would still be worth it to have an professional looking out for you.