Well, speaking of the less known battles, what about Marchfeld (Moravské pole)?
Yeah, Marchfeld is an interesting story. What would you say about Riade ?
How about an example of a battle which is often considered decisive, but probably isn't: Waterloo 1815. It was an epic battle, that analysts have often puzzled over why he didn't win, but no leading figures were killed, and if Napoleon had won, do you think he would steamroller all over Europe again, start the War of the 6th or 7th Coalition ?
His support in France was still pretty shaky, as soon as he got far enough from home embroiled with his enemies, the citizens of Paris would have probably declared their own provisional government, they already ran him out of town once before. Maybe Wellington would not have made PM and maybe some long delayed social reforms under the Georges would have gotten started earlier. Waterloo made the original list only because if nothing else it gave closure and certainty.
There is a probability of course, that Napoleon would score some immediate successes and then adopt a conciliatory tone. Maybe even the other Kings of Europe by now needed some rest after the 'Nightmare of Europe'. Unless some revolutionary movement started early that somehow identified with his cause(?), or there were rivalries developing that split the alliance, I think not.
Now what about Sevastopol ? Huge painful campaign for both parties, but Russia was prepared to bleed a little for her Balkan and Black Sea ambitions. Very little was gained by the Allies. Had they simply settled for a diplomatic compromise, Turkey would still have been isolated against Russia, but that happened 25 years later anyway as their empire crumbled. Britain would not have the
Charge of the Light Brigade and Florence Nightingale, but the lessons of logistics, hygiene, and attrition in large scale modern warfare seemed largely missed anyway. If Russia had shattered and humiliated the allies, it may have fed her ambition and resulted in a significantly different realignment of European powers. I think in judging decisive battles it's easier and more certain to consider the impact of what did happen, because after all, it did.