> Git desperately needs a layer above the commit that groups related commits together into a semantically commit-like object that you can show in history and jump to its HEAD and cherry-pick.

It's called a "branch" :) The commit-like object to represent it is the merge commit.

If you need to group related things in a branch in a more fine-grained fashion then do sub-branches and merge them into the branch with "--no-ff" so you get a merge commit for each to describe them.