One of the things that is most important with the Legion (and, to a lesser degree, the Titans) is a proper balance of action and characterization....you need to CARE about such a large cast.
In his heyday, Levitz was a whiz at this balancing act.
I still think someone like Jim Zub or Christos Gage could pull something like that off with a slightly older, more experienced Legion (Geoff Johns also goes without saying).
What made the books great was they were comic soap operas. Fans were just as invested in who was dating who and what was going on in the personal lives of the characters as what threat they were facing that story. In fact with NTT I would say their personal lives were even more the main story in many issues. Somewhere along the lines comic companies got convinced that their readers were all stupid and all they wanted was big dumb action every month instead of real stories. It is the same reason most characters don't really seem to have any life outside of just being a hero anymore (especially over at Marvel)
I remember reading an interview with Paul Levitz where he said he would make columns on pieces of notebook paper. In the first column, he would list the main plot with all the little subplots underneath. In the second column, he would move everything up and feature other characters. He would continue that over two or three more columns. This helped him map out the main plot and subplots with each upcoming issue so that nothing got lost or forgotten and he tried to write something for every character.
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