At the moment, there are 66 questions tagged with package-writing and 35 questions tagged with documentclass-writing (6 questions feature both tags). Looking at the most upvoted package-writing questions, there are quite a few that would be also useful for documentclass-writing (Note: I excluded questions that already feature this tag):
- What is good practice when preparing a package for CTAN?
- Where do I start LaTeX programming?
- How do I document my style files?
- Write new package with LaTeX2e or LaTeX3
- What are the established methods for filing and tracking bugs in packages?
There are also some documentclass-writing questions interesting for package writers as well:
Package writing and class writing are two related, yet somewhat different topics. The question is, are we better off by retaining two different tags and adding the respective "sibling tag" to the questions that fit both topics? Or should package-writing and documentclass-writing be merged into a new tag called, say, package-class-writing?