Another Rin person here.
To my credit, our personalities are moderately to very alike, so there could be an extra "level" of understanding there. (I believe this is the source of my liking of tsundere girls - however I don't like overly social and overly abusive ones, a bit of "kuu" is good) I also for some reason just can't get enough of dark & long hair style (not the goth kind, but the typical kuudere/tsundere type). All of these put Rin on "waifu" level for me (or heck even at the "opposite sex clone" level at times - needless to say if I was female, Rin would probably be a good example of me).
...on the other hand, this could all just end up in a "tsun" war
Though eventually I actually break down into my "dere" after taking too much tsun and abuse (I will admit that Rin's tsun is probably stronger than mine, but the main core of my dere is deeper due to an outer layer of "kuu" - basically what I call kuutsundere). This higher level of assertiveness on Rin's part is actually good since, um... well honestly I'm pretty sure I wouldn't be the "assertive one" in our relationship. (my mother always said that I'd need a "keeper").
And yes, I am indeed a straight male. (though I do enjoy gender-bending and gender-swapping...did I mention I'm not gay?)
In case you couldn't tell, I've had this thought out for a while