I've been reflecting on years of awful post-tournament discussion, and I've come to the conclusion that much of it can be avoided if question writers follow three rules concerning difficulty:
1. If you know something, that doesn't make it easy.
2. If you don't know something, that doesn't make it not worth asking about.
3. If you think something might be too hard, it probably is.
These rules should apply, of course, equally to post-tournament discussion, but I suppose asking people to keep those rules in mind when discussing a tournament could constitute "preemptive backseat modding," so I'll leave this as advice for writers.