It appears that this could be tied up in the legal process for years.
Unlikely. The RLA is quite clear, and the Supreme Court has verified, that the NMB has the ultimate authority to determine voting rules. In fact, the RLA even allows representational disputes to be resolved without a secret ballot. Again, this has been reiterated by the Supreme Court. There is no legal basis whatsoever to block the NMB from changing the election rules, and I doubt any court would even agree to hear a suit for injunction.