I keep saying this over and over but, Gerrit basically does that. :) You can see the relationships between any two patches on Gerrit, and more importantly, Gerrit shows you each patch individually. So you can see in a series A -> B -> C that yeah, B is small, let's go ahead and get that in.

Part of this is that UX has some really smart ideas like the "Attention Set". The attention set is basically "Which people need to take the next step?" Like a turn-based game. So, if you just did a review, you're not in the attention set for that patch anymore -- the author is.

That means Gerrit puts it down at the bottom of your queue in the UX. And what's at the top of the queue? Things where you are in the attention set! So it naturally groups things this way.

I didn't get into all the other really annoying papercuts with GitHub's UX, but even the pull request listing is worse than the alternatives. How do you know what state anything is in? You don't, you have to go read the whole thing.