I'm going to take a slightly radical approach, as food for thought and just being Devil's advocate...
To me, at the end of the day, it's all music and sound. Yes, there are differences for how you might process an 808 versus a taiko drum, but the same general rules of sound and audio production are in play.
I'll bet that Dave Pensado can mix an orchestral cue just as good as he can mix a pop track because he's got experienced ears and understands the fundamentals of audio production. Sure, he's no Alan Meyerson, but I would still have confidence in him getting a decent mix of an orchestral film score.
in terms of pop songwriting vs orchestral composing... I don't know about everyone else, but when scoring films, writing library tracks, or satisfying a brief, I'm constantly asked to write music that's in a particular style or sounds like a particular song or piece of music. It can be all over the map stylistically, but the process is always the same regardless of genre: listen, research, listen again, compose, compare, finish.
Sometimes part of the research involves coming to this forum and posting a question. And the great news is, I've discovered I can pretty much ask any question about any style of music and get helpful and informative answers. A specific sub-forum for pop, jazz, reggae, hip hop, etc. doesn't need to exist because, as my opening statement said, it's all music and sound.
Yes, the discussions on VI-C lean heavily on the orchestral side of things, but it's just as easy to create a post or ask a question about synth drums as it is to discuss violin legatos. And fortunately, the amazing community here is ready, willing, and able to jump in and provide help in both cases.
So I guess my conclusion is, if it ain't broke, don't fix it