Who says who is an unsung composer and who says he is a sung

[Alan Howe]

Here's an explanation of Wagner's thinking:
http://www.learnclassical.com/the-courses/wagner/wagner-5-endless-melody/
So, my question was how this thinking worked itself out among composers of symphonies...

[Alan Howe]

...just been listening to Scriabin 3. Very much in thrall to Wagner, I'd've thought.

[eschiss1]

The main fast first movement theme of Franck's symphony sounds -very- motivic and short-breathed to me (and an unconvincing fast version of the slow introduction- or vice versa?...) - which is why in my opinion his symphony in D minor doesn't make it in to the modified/evolved thread

[Double-A]

Thanks for the Wagner link.  It matches my recollection quite well.  To me the seductive power of Wagner's music stems more from the harmony and even the instrumentation than from the melody (and Tristan is mostly and justly famous for its harmony).
Anyhow since the concept is so closely linked to the need of "Musiktheater" it is hard to describe what feature you'd expect in a symphony with "unendliche Melodie" (and I insist that "endless" is a bad choice of words for what Wagner had in mind) as the symphony has no choice but to find the drama within the music.

[Alan Howe]

since the concept is so closely linked to the need of "Musiktheater" it is hard to describe what feature you'd expect in a symphony with "unendliche Melodie"

Well, probably some sort of programme for a start  - which would turn a piece of abstract music into a drama.