My biggest problem with Heart de Roommate was how Tomoe and Marumu’s endings are almost exactly the same; that and barely anything happens in Marumu’s route. When we get a little bit of character revelation from Marumu’s brother, I was expecting that to be touched upon at some point in the route but was greatly disappointed when it never came up again.
Indeed. I have noticed the very same after going through their endings a couple of times. (If I have the time, I usually like to try out the same storyline at least twice just to make sure I have not missed out anything as I tend to read too fast.)
I think Marumu’s storyline could have been expanded a bit more. That is, provide more background than the ones given by her younger brother. It kind of felt like her story was put together in a rush. At least with Tomoe’s, the arranged meeting pretty much provided the drama and action to make it at least understandable.
In the meantime, I have recently started getting into Hitomi My Stepsister. I have only tried out Yoko’s endings so far (her storyline seems to be the easiest to run into during my very first attempt), as I still need to wrap up Hitomi’s and Yuki’s routes. On the negative side, her storylines were a bit too quick, and does not consist much more than catching the stepmom masturbating, then getting sexually involved with her while dad is away at work, and some more steamy activities. Things can become rather disturbing at the very last moment: It turns out that Yoko hates Hitomi and she goes nuts upon seeing Takahiro trying to help Hitomi from the cluthes of her abusive mom, and he finds out much too late that she has become very possessive of him. To top it off, there is now infamous ‘Kitchen Knife’ Yoko! Keep her out of the kitchen!!!
There is one thing that makes Yoko a bit unnerving. Her voice is done by the same voice actress who has played Ayame from Crescendo. A perfect voice for portraying a character who appears and behaves outwardly friendly, but beneath that facade … hehe!
Hitomi My Stepsister contains a story flowchart that assistst story branching. Unfortunately, this feature seems a bit of an overkill for Hitomi, since it does not contain lengthy storylines and does not involve complex story branching. This feature would have been much more applicable in titles like Kazoku Keikaku (Family Project) which actually takes quite a while to finish. Too bad …
Useful stuff are always in the wrong games… Why does Da Capo have such a useful recollection section when there’s nothing worth replaying there? Why does no other game have that? 
There does not seem to be a consistent basis for including replay feature other than when a title was released. For example, Heart de Roommate and Yume Miru Kusuri allow replaying previously completed chapters/sections. Older titles like Kana Little Sister and Private Nurse do not have such. I have not tried out the most recent titles, so I wonder if they carry such feature.
Practically every eroge nowadays has a H scene replay feature. Ones that allow you to view scenes other than H scenes, on the other hand, are still few and far between.
I’m Going to sereve you 4- really good game, I really enjoyed this one from start to finish