That seems fairly reasonable; I assume that there would be routes for both democratic and revolutionary change, but some sort of Austro-Hungarian lock on power will push the other states towards the latter. I'm also assuming that this would not need to be (initially) justified by eg population or franchise, and without express instructions, nothing would change - so even as the voting population favoured the other states, the political power would still remain with Austria-Hungary. (I know this is kind-of just a summary of what you said, but that's mostly because I want to have understood correctly.)
You suggest using revoltable tags as states, so I guess they form pretty nice nation states (I would of thought given the complexity, around six would be optimum, at least to start with). In the case of conflicts between tags, can we think of a logical system as to which takes precedence, or are we just going to manipulate the map to get a nice number of states. Which areas qualify as states? Do the Italian provinces count as 1 state, 2 states or no states? Would they have elected for independence in preference to joining a Danubian federation? Would the Czechs and the Slovaks be together or apart? Would Hungary retain its large tracts of Romania? What would happen to those provinces now in Ukraine? Would Serbia or other states not part of the Empire have risen up in the hope of joining? (sort of like Texas [?]) [EDIT: see next post]
In addition to this, given that the game starts in 1836 and our diversion from history would come in 1848, are we going to try and recreate the world in 1848 or just play until we're in that situation? In terms of Austria this is easy, because, as far as I can tell, there are no changes in this period, but what of the rest of the world?
Sorry for just posing lots of questions, but giving no answers... Maybe I'll add my thoughts on possible solutions after a little thought.
PS, Gloa, you will be RoleplayAAR of the month for January 2013. Congratulations.