The title on this one's not very clear, so allow me to elaborate on what I am proposing. As we all know, in canon, Ranma had no idea that Ukyo was really a girl until after Genma got him engaged to her behind his back, abandoned her on the road and she tracked him down in Nerima a decade later. However, it's quite a chain of coincidences in canon that Ranma just happened to leave her without knowing she's really a girl. So, what if one of those coincidences broke down? Something happened to cause Ranma to learn that Ukyo was his best friend and a girl, even though he still didn't know about their fathers engaging them and left her behind carelessly until she confronted him in Nerima as a teen?
What do you think would happen, in this timeline? Considering that, this time, Ranma would probably actually say something like "wow, Ucchan, you always were a tomboy but what's with the guy's getup?" when he meets her?
I do have some vague thoughts on the subject myself... but, seeing as how the original "slant" I followed after coming up with this idea was distinctly aimed at a Ranma/Ukyo pairing, they might be too biased to include here. Let's just say that, coupled with something Ukyo said before they parted (can't actually remember what, now; think it was vaguely "boys and girls grow up to get married"), Ranma was never really happy about being engaged to Akane, and he would actually sometimes wonder what it might have been like if he had been engaged to marry Ukyo and/or fantasize what Ukyo must look like now she's grown up before Ukyo actually showed up in Nerima for real.