Why does the first two relatively simple operations have have simple implementations, yet the third, which still sounds simple, has a wildly different level of complexity in Grasshopper?
Have I misunderstood something, or is this just the way it works?
(Solution came from this search result.)
Ok, wait… I did notice a difference in your solution… so this does actually make it a bit simpler:
Thanks, @dowazura
Could you upload the .gh file? 
The old (2010) thread you referred to gave you the answer:
Why does the first two relatively simple operations have have simple implementations, yet the third, which still sounds simple, has a wildly different level of complexity in Grasshopper?
You are right that tree level manipulation should at some point be as easy as item level manipulation. Most probably in GH2 it will be I imagine. In the meantime, I suggest Tree Sloth as it really covers most of those pesky tree operations we tend to run into and I imagine they will become a standard part of GH in the future (we shouldn’t be thinking about how to remove a branch, we should be able to just remove it). Luckily McNeel made it very easy to write tools for their software because they want the users to fill in the blanks. In this case you can use Trim Ends component (even though for this specific case the regular gh way isn’t difficult).
Specifically, I find the Flip Last component most useful which lets you flip matrix a multi dimensional pathed tree.
