I really like how the difference between Douki-chan and Tawawa is shown here: Tawawa is quite confident in herself and her relation to her MC (whatever that relation is), while Douki-chan is often jealous because she is insecure about those things.
I really don't expect the "Douki-chan" manga to get more developed storytelling than it already has, but it's nice to see that the author has a clear idea of the characters' personalities in special issues like this.
"Tawawa" began like a collection of random girls with oppai, but eventually had several recurring characters evolve. I like how they were all made a part of this story, together but separate.
Also, I can't help but wonder if "Senpai's senpai" in "Douki-chan" really is after the MC, or if she's just trying to put some pressure on Douki-chan to make a move...