Even if a romantic artist create a work that I liked equally as much as a Mozart and Haydn composition.
The fact is that I logically know that the elements I like about Haydn and Mozart were things that influence and led to the development of Beethoven while the elements I like about let say Schubert, Brahms, Mendelssohn, Berlioz, Liszt, Mahler, Tchaikovsky etc is because it reminds me of Beethoven.
I appreciate the influence of Mozart and Haydn but I appreciate the nostalgia of romanticism. The original elements of romantic works (such as programmatic elements, loosening of tradition harmonies, break down of classical forms, lack of tasteful emotional restraint) are all negative attribute of the era
Essentially the best elements of romanticism is Beethoven nostalgia and the worst elements of romantIcism is it's originality
Any sort of perceive weakness in pre-Beethoven composers I can just rationalise away as them forming important building blocks that lead to Beethoven but the weakness of romantic composer is them moving away from Beethoven. Moving toward perfection is a lot more enjoyable then moving away from perfection