Too... ordinary. I saw stories like this so many times that it seems so boring now.
"I will graduate and move to another city but our love blah blah blah..."
The scenario you found ordinary is pretty rare in yuri. Actually, it downright hardly ever happens. This is the only story so far with the kouhai-senpai graduating narrative that does not end in "she'll grow out of this 'phase'" or "this is a naive memory of youth I won't forget." (Some yuri stories just love spiralling into that angst...)
I know this is an old comment in an old discussion but I just can't help pointing this out. I know this is just porn, but still it is one of the rare stories (I don't know if there are others like this, will be glad to get more examples) that got over the tantalizing "girls liking girls is a phase" mindset in Japan. That mindset is still going pretty strong even in the present (it is used to justify gaybaiting...).
So yeah... I'm really happy they got a hopeful ending haha.