This developed when I was watching Leonard Bernstein - The Unanswered Question on youtube.
One of the descriptions of Mozart's music using the example of Symphony No. 40 was the balance of chromaticism and diatonism. His melodies in that piece were highly chromatic using notes, not in the scale but the way he harmonise helps "regulate" the dissonance.
The most extreme example was the development section of the 4th movement of Symphony No. 40 where he used 11 out of the 12 tones (the only tone missing was the tonic) and Bernstein described that even in that section he was able to balance it. From further reading of this section, this is often used as an example of the predecessor of the 12 tone technique by Schoenberg.
The implication that I get out of this is that it doesn't really matter how chromatic the melody is as long as you balance the melody with appropriate harmonisation it will still sound coherent and make sense to listen to.
So what is the next step to follow the footsteps of Mozart and take this balance of chromaticism/diatonicism to the next level of development?
Synthesise diatonicism with 12-Tone Technique.
Use the 12 tone row as a pure generator of melody and ignoring all the other process involve in the 12-tone technique to ensure the music is atonal (so ignoring the Hexachordal combinatoriality etc)
Treat the 12 tone row similar to a chorale melody to be harmonised with traditional tonality.
The composer melody has to use all 12 tone tones before repeating itself, once the prime tone row is completed this will be followed by another tone row (which could be transformed via transposition/retrograde/inversion) and then this is repeated indefinitely until the end of the piece. However, the underlying harmony underlying the tone row follows traditional harmonic rules similar to what we hear from the Baroque to the Romantic era.
The function of this technique is to use the tone row is not used to create atonal music rather it is used to maximised chromaticism within a tonal piece of music. By maximising chromaticism you'll have music that has the same beautiful emotional ambiguities that are present in Mozart's music. This may produce interesting results but still, be comprehensible by the population (unlike the majority of serial composition)
As a result, you will take Mozart's balance of chromaticism/diatonicism to the next logical step. You would also unify 12 tone technique with tonal music and bring things to full circle by using Schoenberg's 12 tone technique to advance the development of tonal music when in the past he has been blamed for destroying tonality. This also helps connect the influence between Mozart and Schoenberg explicitly (Schoenberg insisted that he is a student of Mozart).