The problem with that is that the legalese version of the contract is supposed to be definitive. If they also provide a plain english and one of the terms when exercised invalidates a "plain english" provision, how is that supposed to be interpreted? In this case it was one of those details that mattered greatly. A plain english version would have just said "you get X options you can exercise on this vesting schedule, subject to terms(*)"
That doesn't seem to fix the underlying problem -- they understood/read the plain english version, just not the terms.
Honestly (and I'm guilty of this as much as anyone), I doubt they even read the terms. Here we have this huge thread about contract language being hard to understand, but if one doesn't take the time to read through, understand, and _remember_ all the terms of the agreement, how can one act on that information?
It would be interesting to have a contract that had questions that must be answered at the end of each section. You must answer the questions correctly for the contract to be valid. And the question must properly represent the section -- that is, poor questions could invalidate the contract if challenged.
This would make it important for ppl to read the contract, and would push lawyers to make them simpler to read, and would also make it harder for ppl to push contracts onto people who don't really understand them.