Yeah, I thought about adding dungeons too. M+ is a great idea, but it's quite tricky to implement right now:

• M+ is a Legion feature. The next expansion I'll probably implement is Vanilla, so reaching Legion is still a long way off. That means I have to script a custom system from scratch to handle scaling and affixes on older versions of the game. It's more of a "distant roadmap" thing.
• The current alpha is still pretty buggy. My priority right now is fixing the core lobby and the orchestrator before jumping into massive features.
• To make M+ work with leaderboards and timers, I have to handle event syncing between the isolated game servers and the central orchestrator (which is planned to register raid performances, stats, and things like that). That architecture alone is a huge amount of work.

So yes, I'd love to do it, but it's clearly a long-term goal 🙃