Well that's a difficult question. The only way I can see the compromise being aborted would be if Austria beats Prussia in the Austro-Prussian war. That defeat is what gave the Hungarians the leverage to make their demands. But, assuming that the Hungarians don't get their way AND remain in union with Austria (it is possible that the Hungarians will try to break away again) then first off, they won't be able to hold the Empire hostage and prevent any meaningful reform. That in itself is a massive plus for Austria. Second, I can see the armed forces of the Empire being stronger, sense there is only one military budget, rather then two. Besides that, well I'll have to think about it.