Let's look at sometimes maligned or shirked figures in classical music: Franz Joseph Haydn and Wolfgang Amadeus Mozart. Both, among academics, are considered to be among the greatest composers of all time. Among much of the public, however, they are known more for making "easy-listening" parlor tunes or music for babies than for creating high art. It's inarguable that the raw emotional content in Beethovian symphonies or Schubertian lied is much more accentuated than the comparably subtle piano concertos of Mozart or string quartets of Haydn, but people often forget that the former two wrote their best music 15-30 years after the latter. Beethoven is as much a contemporary of Haydn/Mozart as Radiohead a contemporary of Zappa.
Comparing these two groups is not fair, then. Instead, we should compare Haydn and Mozart to their actual contemporaries: names like Vanhal, Stamitz, Hoffmeister and so on. You've probably never heard these names in your life; or, if you have, it wasn't a particularly impressive work that you heard. That's because these composers were very focused on formula while Haydn and Mozart were focused on moving forward. Haydn in particular is almost entirely credited with nurturing the symphonic form into what it's been known for up to this day, whereas Mozart was known for (comparably) rather avantgarde tendencies in shifting around form and harmony. Once again: there is no comparison between what is accomplished in Mozart's Clarinet Concerto and the myriad of Clarinet Concerti by Stamitz.
What we see then is that, even in the most tuneworthy of composers, there must be innovation; ever since Beethoven, innovation has been an absolute component of "classic composer status". Wagner, Debussy, Stravinsky, Bartok, and Schoenberg were all innovators the same as Haydn and Mozart. There is not a single Common Practice composer who is fondly and widely remembered solely for their enjoyable melodies, and not for their innovations.