I'm not arguing against the CST format, but I don't think redundancy is necessarily bad or hard to work with. It can be good because each line is now an indepe

I'm not arguing against the CST format, but I don't think redundancy is necessarily bad or hard to work with. It can be good because each line is now an independent idea and doesn't require the indentation context, the items can be sorted or moved easily. As for hard to work with... a lot of editors have multi-cursor support these days, which makes editing these things in bulk pretty straight forward for smaller sizes and then there's always sed and awk. ;) Given all that, CST seems like it might be cool for building some quick trees like the given UIs you present. I'd probably keep to to rows for longer storage though.