The java one seems to use an old version of java, doesn't support lambdas for sure and possibly auto boxing, currently complaining of a runtime error that works perfectly on my machine.

I agree

Yeah, I think you have a point. The vast majority of software development is done in a shoddy way, this includes Scrum and other agile approaches. However if you have a high performing team they will do better using these approaches. This is the big secret that none of the books will never tell you. With a great team you can do any methodology and be successful, with a shit team you'll always fail. However I think with a great team you'll get more done and higher quality using agile approaches verses something like Waterfall or RUP.

Yes, this is on my list to look at. I wonder what it might give beyond Lisp or Haskell though - any idea?

Sounds like Scrum done wrong - you need to reserve time to payback the debt each sprint - easier said than done I know but I don't think any approach gives you this for free.

Alternative? Waterfall is worse in my experience, as the massive project creeps toward a big bang role out more and more desperate decisions are made to meet deadlines.

I agree with you, however getting the balance right is key. Many companies make bad decisions over very long time frames, each decision justifiable in its own right leading up to complete failure. For example many of the banks in the UK are facing significant IT failures due to their technical debt (e.g. charging cards twice, customers unable to withdraw funds). These situations happen one tiny step at a time. A good delivery team are responsible for their quality - you can't blame it on someone else.