Maybe you should cut back on the garbage answers, like the OP will "spend thousands on your lawyer to sue and get the same or worse outcome".
First off, there's no reason to spend thousands on a lawyer for a case like this. He's got a contract, signed by the builder, specifying the changes. He can represent himself in small claims court.
Second, filing in small claims court now increases the builder's cost for breaking the contract significantly, because they probably WILL send a lawyer. This will increase the odds of them deciding to settle out of court at more favorable terms to the OP.
Finally, it has nothing to do with the builders being "fairer". And frankly, I don't give a flying fig if you judge me or not.