I agree that keeping Angrod alive post-Dagor Aglareb allows us to finish up his arc with some sort of reconciliation (or attempted reconciliation) with the Fëanoreans. His and Caranthir's feud has been carried out by proxy, for the most part. If we come up with an excuse to put them in a room together in Season 5, I think it will be worth keeping him alive at least a little bit longer.
As of right now, the Fëanoreans just arrived to save the day in the Dagor Aglareb. Angrod (and Aegnor) had been expressing doubt that they would do so, or more like the sentiment that you can't count on Fëanoreans for anything. So, yeah, possible change of heart opportunity here? Or he could become more bitter over the death of his wife, blaming them for not getting there sooner. Regardless, that's an aftermath-of-the-battle question that he won't be around to address if we kill him. Leaving him wounded in some way might be good.
I have some doubts that having Gothmog slay a distraught Edhellos would do anything to make balrogs look fearsome. She's not exactly in the best shape during that encounter, and killing someone who can't even determine if you are really standing there is an easy task. Having Angrod and Aegnor rush in to save her and fail to inflict any injury on Gothmog might make up for that, though.
Basically, we are choosing between killing Edhellos + Angrod now, or Aegnor + Angrod in the Dagor Bragollach towards the end of next season. Either way, Angrod is the +1 death that is less emotionally impactful than the other character he's paired with. I suggest that we choose neither option
I would like Angrod to be missing, presumed dead, after the Dagor Bragollach. Aegnor dies, but Angrod is taken captive to Angband...where he meets Díriel, who knew Edhellos in her captivity and is of course Curufin's wife and thus a Fëanorean. That could be an interesting end note to the feud - both Angrod and Díriel would remain prisoners in Angband forever, and while the audience will see them again, the elves never will.