At this point wouldn't it seem a bit of a genre change if they became a couple? At first that's what I wanted, but as I read on it just seemed less and less likely and I'd rather preserve the essence of the story rather than just fanservice. Then again, maybe I still wouldn't mind the yuri...
wah? on this i respecfully disagree. IMHO, it would make more sense if they became a couple and I do not see it as a change in genre. i say this because what we have been seeing for 26 chapters is a slow progression of their friendship from simple roommates to something more akin to family. that said, it is not a far stretch (pun intended) if their friendship progresses to the romantic. why? because we have been presented with coy glances, blushing, cutsie offhand comments... i argue that these examples are the foundation of a relationship. nothing fast. nothing topsy-turvy. just a nice slow progression. that said, if they never become a couple, then that is also ok because they would have a very strong, loving, non-romantic bond which is equally as valid as if they were a couple.
Although I do view them as a very loving pair of friends at the moment, I get the feeling that Ran might be a closeted lesbian who's in love with Keiko - you have references to how she seems uninterested in guys, although she is popular with them, and, I don't know, there's just a sort of undertone with some of the things she says to her. The "cherry-popping" comment is fanbait, sure, but usually when there's fanbait the characters themselves will be unaware of the innuendo, and that is certainly not the case here: Shou has Ran say 'I'm glad this is your first time', which is the usual level of "innocent" service, but then very deliberately follows up with the 'I get to pop one of your cherries' thing, which has overt sexual connotations. Even the normally quite oblivious Keiko notices.
On the other hand, Keiko herself is probably straight or unaware of her bisexuality, giving off a much more friend-like vibe - her touching Ran's hair and groping her generally comes off as innocent interest and admiration (that sounds so positive) rather than lesbian attraction. So while I think that Ran has actually got a fair chance of being a closeted lesbian - which would be incredibly cool if it were true; I'd have to praise Shou for being able to handle the whole thing fairly delicately and realistically - I doubt that she'll get together with Keiko unless she confesses or otherwise makes her feelings obvious. I may be completely wrong, or maybe it just won't happen. But man, do I wish that would it would. Rooting for them all the way, even if they're only just friends without romantic feelings for each other!