I agree with much of your thinking. So the question is, do the Estates General get called at the same time, even if the debt is in a better situation? Or will there be more attempts to go through the parlements?
Another thing I don't quite get is that many of the Cahiers du Doleances from the Second Estate seem to suggest they would accept new taxes. Yet at the Assembly du Notables and in the Parlements, they were intransigent. I'm wondering what caused them to change their tune, even if it was only slight.
Well, as said below, the money could end up squandered in the Bavarian War of succession, but then again we have to remember years before that Louis XV refused to intervene in the Polish partitions, most likely because of the state of the army at that time, but also because of the debt from ythe Seven Years War. If Louis XVI doesn't get involved in the ARW, he's likely to sit out the Bavarian War of Succession too. Despite the alliance with Austria, the new queen really had no pull over policy and at times Louis XVI could be quite Austrophobic, so would be more likely to sit out than do anything to aid their ally.
The big reason the Parlements became instrasigent was over the so called Lettres de cachet. These were basically bills signed by the King and a minister and stamped with the royal seal which essentially forced a Parlement to accept and register a law that it had refused to do so on his own accord. By the late 18th century there were already demands of for it's suppression, as the lettres were not typically used to pass legislation, but more popular as use to arbitrarily imprison those who protested against the crown.
The biggest issue with the Parlement of Paris, and indeed most provincial Parlements was the privileges they were seeking to preserve for the noble and even bourgeois classes. Indeed, it was through the Parlements that the bourgeois could even rise up into the nobility. The beginning of the issues began in 1776, as the nobles protested any attempt to remove their exemption from taxation. This issue had ran back into the reign of Louis XV, where the
Machault d'Arnouville in 1749 attempted to reform the levying of direct taxes.
The biggest problem with expanding France's main tax, the Taille, is that those subjected to the Taille were also technically subject to the corvée. which was essentially forced labor for a set amount of time (typically three days) which could be used by the aristocracy for peasantry upon their estate, typically once a year, or by the state.