My idea for STACK would be to work on the installation documentation and offer easier ways of installing. For example full instructions on installing on some leading cloud providers. I have installed STACK on multiple occasions and over the weekend I tried the goemaxima approach (possibly the future for STACK), and I would have had no chance without my previous experience with STACK/maximapool and docker. I know that is not very "developerey", but it would be a big contribution and we would be guaranteed to have something of use to a lot of people at the end.
What about the creation of an AWS AMI image, just add water/sysop, et voila working stack back end...
