Ability to easily split a commit to break it into multiple commits (using rebase)
When working on a branch, it is very common that you end up realizing after the fact that one of the commits you made should actually be multiple commits, whether because the MR/PR reviewer requested you to do that for clarity, or because you suddenly want to be able to cherry pick a portion of the changes to merge them independently.
Currently, to split commits, your only option is to use git rebase
and do a somewhat confusion-prone/abstract set of steps, like those found in this answer.
It would be absolutely amazing if gitg could let us do that graphically instead: you right-click a commit, select "Split this commit…", and you then enter an interactive rebase (depends on #4) where you can then re-stage the changes of that commit into as many new commits as you want.
Basically, just automating a couple of steps from that linked answer tutorial.
An example of another Git UI application offering this feature can be seen in this short video.