I have an important point to make about an enduring myth about Austria-Hungary (and since it's already been pointed out that Franz Ferdinand was an awful person, and I'm too sleepy to defend FJ and Karl) and it's about the Ausgleich 'renegociations' and I 100% blame Kaiserreich for propagating this myth.
They never happened. At least, not in the way people think. It's not mentioned in any of the books I have on A-H and I would seriously think something that would threaten the Empire evey decade would be important enough to mention.
What WAS to be renegotiated every ten years, however, were the economic terms of the customs union, not the political Ausgleich. That is, IIRC, the balance of the budget for the Common Ministries (Foreign, Finances, War) and the customs union itself. Basically, even by 1867, the Hungarians weren't aure if they wanted to go full-Free Market with Austria or towards protectionism, a debate that had been going on since the 1830s. Of course, the success of the Union and the massive economic growth meant that the Hungarians would never repudiate it. After all, as previously mentioned, Hungary needed Austria as much as the latter needed the former. Politically and ecnomically.
Secondly, people tend to forget how broken the politics of Hungary were pre-1918. It was a shitty system were the noble magnates had way too much power and the suffrage was ridiculously limited. Remember, iOTL, Hungary fell to a communist revolution. While without the war, discontent wouldn't be so radical, Hungary is hardly a united, anti-Vienna and pro-independence bloc. It was the complete opposite. During the war, the government had to compromise and promise to expand suffrage. I don't see why the call for reform wouldn't happen iATL even without the war. Vienna wouldn't want Budapest to ruin the Kingdom of Hungary by continuing their Magyarisation policies and angering both ethnic minorities and the commoners. The Hungarian system would, in my opinion, collapse much more quickly and easily than the Empire itself.
Basically, Hungary needs reform as much as the Empire as a whole. Whether the Nationalists want to or not, the Hungarian magnates are going to be forced on the negociating table and it's either going to be with Vienna or an increasing amount of political radicals. A clever one in Vienna couls very-well take advantage of the increasingly-unstable situation un Hungary to push for reforms.
In the end, Hungary was far from disloyal as people keep trying to push for the past 99 years. Especially not in 1914. I don't think it could've stood up from a more reform-minded Vienna by the late 1910s. Not without its own growing problems becoming more and more glaring. I'm certain the Hungarian magnates wouldn't risk everything in order to maintain a degrading status quo. They had less to lose from reformsn after all.