A majority of my development is in Node, Java, Ruby, and eventually ASP.net 3. I haven't run RPi-Monitor but I'll be installing it as soon as I have time (the next few days are busy for me) so maybe I can find the choking point. The underlying OS to my knowledge of the hypriot image is Raspbian, and to my current knowledge that isn't the most optimized, so then you put Docker on top of it and I can only assume it's not the best.
Your link is one I missed, and it is interesting. I think the CPU is fine, my error logs state that the containers are running out of memory so hopefully I can see see what up a bit better with RPi-Monitor. Even with that said though, I am interested in more powerful SoC's that are available or are soon to be available. The Banana M3 interested me, but your write up on it has me holding off on it, the Pine seemed promising but it too is down the same hole. I'm now looking at the Cubietruck and the ODROID-XU4 as possibilities.