I've always had issues trying to fit The Nirnaeth into series format. The guy who did the Silmarillion series website tacked it onto the end of the B&L season, which I felt was not giving the battle it's due. But I also feel the season 7 you outlined is pretty lacking in content, until the battle itself. I think it would be very hard to fill out 13 episodes like that.
My last post was not really an outline so much as suggestions for things that could happen in the season. There are many other things we could include, e.g., Gelmir captured and Gwindor's reaction, Fingon becoming high king, the arrival of the Swarthy Men, the doings of the Haladin, the retaking of Dorthonoin, Thingol getting dangerously obsessed with the Silmaril, Galadriel and Celeborn in the east, Sauron in the east, a Gondolin storyline of some kind, etc.
I think there is plenty of content to flesh out a season. Most of these are not events; they are arcs that would be told over one or more episodes. Hurin and Huor in Gondolin need not be a scene or two; there could be a whole episode or more devoted to the differences between Elven and Human perspectives in Gondolin. Think of how many groups are involved in the Union of Maedhros: Feanorians, Fingon's people, the Edain, Gwindor's company from Nargothrond, Beleg and Mablung, the folk of Bor and Ulfang plus the other Men from the east they send for, and Dwarves of both Nogrod and Belegost. There is a lot to do to get them together, and Maedhros does not even start doing so until after Beren and Luthien get the Silmaril. That could certainly take multiple episodes. Also, the Nirnaeth itself could take sevral episodes. We talked about the Dagor Bragollach taking two episodes, and if it does, the Nirnaeth should take at least as many, if not three or four episodes.
I am also worried about what the Nirnaeth would do to the tone of the Beren and Luthien season. I am afraid it would drastically overshadow the happy(ish) ending of that story, which I think would be a mistake.
