I hear ya, but neither Stack Overflow nor Reddit are true forums. SO is a Q&A site format, and Reddit is affected by temporal ranking decay in a way different than traditional web forums and boards. Reddit and HN are essentially topic aggregators, which lend well to trends and current activity but not to long term forum discussions. I'm an active member of forums that have two or three year old threads that are still active on a daily basis. Because of the algorithmic ranking system of HN, Reddit, etc, you'll simply never get that.
I am honestly not doing too much to promote the forum other than posting it here and attempting to reply quickly to everything. A few dozen folks committing to the forum in the interest of getting it off the ground could easily start it moving forward momentum wise. I'm open to running ads somewhere to get traction, but there aren't many places I think that would be conducive to ads.
As for design, I just used one of the free themes available for MyBB. The homepage is very similar to many other forums online (such as anything powered by vbulletin). I can start looking around for themes that show more details/activity though.
I certainly appreciate your feedback and would love to incorporate as many updates and enhancements as possible to get things moving. Quite honestly, I would love for even just half a dozen people starting threads and answering replies and we can start to get the ball moving. After that, it should be able to grow fairly organically.
EDIT: I found this plugin that I will go ahead and install: http://mods.mybb.com/view/recent-topics-on-index-page that will show recent threads on the home page. I think that's a decent solution for showing more recent activity to users.