It's unfortunate that the peace deal was not between the Israeli Defense Forces and the Egyptian army. The longstanding treaty is between two sovereign states, not the guys with the guns charged with protecting said states.

A Muslim Brotherhood-dominated Egyptian government could still decide to abrogate this treaty.

As such, the Egyptian military's reassurances are pretty much worthless, unless they're planning on openly running the country - which is a possibility fraught with far more uncertainty than letting civilian elements of Egypt's political spectrum sort themselves out.