no allegations coming from here. Facts are facts. I'm pretty sure that Alexander was a dictator. Francis was a bit less so. The Habsburg style of rule meant that there was usually some need to compromise and build a coalition inside the government. (See the all the politics involved in the build up to the 1809 war with the war party and peace parties inside the government.) George III was certainly not a dictator for the reasons pointed out. The kings appointed by N. were really vassals of N. with absolute rule within their realm but still beholden to any demands coming from N. Who else is there? It's easy to rate rulers as to where they are on the scale of being a dictator or not. Again, the greatest power any ruler has is the declaration of war. Only a dictator can personally order a nation to war without any other consultation of state; like N. did in 1812.
N.? As already stated, there are plenty of reasons to call him a dictator. He does things that we expect dictators to do. I understand that there was a finely functioning government administration under N. (no doubt the trains would have run on time, if they had them) but, as previously stated, nobody seems able to point to any legal restraints of any sort on the Emperor. He appears to have been an absolute ruler, it appears to have been an one-man rule. If he wasn't, you would be able to point to those restraints, but, you can't.. at least so far.
The rejection of the fact that N. was in the modern sense a dictator seems to be more based on emotion than logic; Is it that dictator is such a bad sounding word and since N. was so great that applying a bad sounding word must be wrong?