"But note this doesn’t mean everything will be perfect. If the acquirer decides that you are no longer needed, they could keep your option agreement intact and terminate your employment. You wouldn’t get any further vesting unless you have single-trigger or double-trigger acceleration, and you’d be out of a job. It would be the same as if you’d been fired by your company before the acquisition."
Maybe I'm reading this incorrectly, but if you don't have single-trigger or double-trigger acceleration, the employer has all the leverage they need to renegotiate your (incentive) contract.
You're right. That's true the before the acquisition and after. Your employer can say you have to accept a reduced package or get fired.
The difference is the starting point of the negotiation. If the acquirer wants to keep you, the "right" language in the option plan means the starting point is your original comp package. You have to explicitly agree to a reduced package for it to change. If you have the "wrong" language, there is simply no deal in place to start the negotiation.
(without knowing anything about this stuff) it sounds like the difference is that they must fire you if they don't continue your "award" or give it all to you immediately. This takes away the possibility of bluffing on your part / calling your bluff.
You can honestly say, "sorry, not my decision, I can't stay if I don't get all my options (now or on schedule)". That could be a somewhat stronger negotiating position.
Maybe I'm reading this incorrectly, but if you don't have single-trigger or double-trigger acceleration, the employer has all the leverage they need to renegotiate your (incentive) contract.