First issue, 7th Amendment:
The amendment says that the right to a jury trial shall be preserved. Note that it does not say “extended” or “granted”. This distinction is acknowledged universally in cases dealing with the 7th Amendment. If there was a right to a jury trial in the action when the Amendment was adopted, that right is preserved. So unless the action was one which allowed a jury at common law as of that date, the Amendment has no power to extend that right. It just prevents the Congress from making a law that would eliminate that right where it existed prior to the adoption of the Bill of Rights.
Second issue, Arbitration agreements:
Courts are VERY hesitant to use “unconscionability” to destroy a contract or provisions thereof. There have been challenges to arbitration clauses on those grounds, and they have failed. My Civil Procedure professor is one of the leading minds in the fight against these clauses, and she concedes that most of these clauses are not unconscionable.
Carnival Cruise Lines was involved in one of the more widely known cases on choice of forum clauses, and their winning argument was that so many suits are brought against them and other corporate entities every year that it is more efficient for the courts to allow these clauses, and that it would be almost impossible for Carnival to send agents to the large number of courts across the country that might have personal jurisdiction over the company. So they consolidate all the cases against them into one jurisdiction in Florida, and purchasers of cruise line tickets were held to agree to this by buying the ticket with the clause printed on the back of the ticket. Forum selection clauses are not the same as arbitration clauses, but the reasoning used by the court indicates that they would be likely to extend that reasoning to arbitration.
Third issue, Jury trials and Contracts:
A contract dispute involves far more matters of law than matters of fact. Juries only determine matters of fact, they don’t decide what will be allowed or excluded under the parol evidence rule, they don’t apply the statute of frauds, and most haven’t even heard of the word “estoppel.” Often the judge, already making most of the important decisions, is the fact-finder as well. There was no right to demand a jury trial in all contract actions at common law, so the 7th Amendment provides no protection
As a personal preference, though I disagree with some arbitration clauses (specifically, those included in software EULAs, which are a matter for a whole thread on their own someday), I don’t think that an Amendment granting a right to jury trial in those cases would be appropriate. The best way to try a contract action is with a bench trial. The factual considerations are interwoven with the issues of law, and as such the judge is the best person to make those determinations.
That being said, as these clauses become increasingly egregious (see lucwarm’s example) public opinion will turn against them. I just hope we don’t do something so rash as alter the Constitution to put juries where they don’t belong.