I don't see a Napoleonic victory at Acre changing much. In fact, it might make things worse for Napoleon. Cut off as he was, his army was slowly wearing away through attrition, and extending his reach into Palestine only made things worse. Logistically, and with such limited troop numbers (the expedition to Palestine consisted of 13,000 troops, IIRC), I cannot see how much farther he could have gone.
The Turks were already planning the naval expedition against Egypt to reclaim that province from Napoleon. IOTL, this was completely shattered by Napoleon at the Battle of Aboukir, but would it have been had 10,000 of his troops been dangling out in and around Acre?