I really do like AribaWeb having worked with the commercial products for the last 16+ years, however I think AribaWeb has 3 major issues:
1) it's not responsive and the entire UI is geared towards desktop browsers, so 60%+ of your users are going to be using a less than stellar UI
2) Learning AribaWeb really won't benefit you going forward since it is a unique product. Your knowledge of AribaWeb really doesn't help you with anything else. But if you spend your time learning something like Spring, it's knowledge you can continue to use for many different purposes. Even for a non-programmer, there are 4GL products that can build you a front end to your database app.
3) We could fork AribaWeb and build a great responsive UI front end, but this is a pretty decent amount of work and I'm not sure what the benefit would be. I was considering using AribaWeb with Apache OfBiz, but again there are better solutions out there.
I think AribaWeb was worth releasing to the public domain as it gives an insight to others on what a true ORM based solution can look like (compared to to the JavaBeans mess), maybe it can be considered a reference implementation.