I'd say incredibly low.
The combination of Austria becoming more interested in Italy and the Balkans, the rise of Prussia as a powerful state both east and west of the Elbe, and the end of ecclesiastic states in the German-speaking world really make a formal restoration of the HRE very unlikely.
Half of the College of Princes thus no longer existed and the Bundesversammlung, as an institution, was far more balanced than the secular half of the House of Princes, with its eleven independent votes and six plural votes for groups of smaller states. It should also be noted that the German Confederation didn't have a formalized head, and while there were discussions to introduce such a position, they ultimately failed because everyone knew it would either be the King of Prussia or the Austrian Emperor who would become "president" (Austria's own imperial title was also explicitly created to allow the Habsburg to maintain an imperial-level title without risking losing it, especially to a foreign invader like Napoleon). Plus the surviving/restored Electors (Baden, Bavaria, Bohemia/Austria, Brandenburg/Prussia, Brunswick-Lüneburg/Hannover, Hessen-Kassel, Saxony, Württemberg) were a mixed bag: Baden and Württemberg were often seen as "upstarts", while Saxony could consider itself lucky to still exist, and Hessen-Kassel was a minor player in the grand scheme of things.
If, for some reason, a more centralized Holy Roman Empire would have been created, or the German Confederation more closely modeled on the HRE, then it likely would have been a more unstable structure, and the 1848 Revolutions may have caused it to not get restored even if the revolutions were still crushed. Instead an adoption of the Erfurter Union or a permanent north-south divide would likely have replaced it then.
The combination of Austria becoming more interested in Italy and the Balkans, the rise of Prussia as a powerful state both east and west of the Elbe, and the end of ecclesiastic states in the German-speaking world really make a formal restoration of the HRE very unlikely.
Half of the College of Princes thus no longer existed and the Bundesversammlung, as an institution, was far more balanced than the secular half of the House of Princes, with its eleven independent votes and six plural votes for groups of smaller states. It should also be noted that the German Confederation didn't have a formalized head, and while there were discussions to introduce such a position, they ultimately failed because everyone knew it would either be the King of Prussia or the Austrian Emperor who would become "president" (Austria's own imperial title was also explicitly created to allow the Habsburg to maintain an imperial-level title without risking losing it, especially to a foreign invader like Napoleon). Plus the surviving/restored Electors (Baden, Bavaria, Bohemia/Austria, Brandenburg/Prussia, Brunswick-Lüneburg/Hannover, Hessen-Kassel, Saxony, Württemberg) were a mixed bag: Baden and Württemberg were often seen as "upstarts", while Saxony could consider itself lucky to still exist, and Hessen-Kassel was a minor player in the grand scheme of things.
If, for some reason, a more centralized Holy Roman Empire would have been created, or the German Confederation more closely modeled on the HRE, then it likely would have been a more unstable structure, and the 1848 Revolutions may have caused it to not get restored even if the revolutions were still crushed. Instead an adoption of the Erfurter Union or a permanent north-south divide would likely have replaced it then.