I would also welcome Tao and Ragna being together, because in CS I remember in Ragna's story that he acted like he WANTS to hangout with Tao, and even OFFERED her food...of all people and didn't of her as annoying..it looked like he actually like her... also what Jubei said of asking Tao to take care of him.
to me this is what Ragna acted like towards the chars (in CS/2/E):
To Noel: screw off, leave me alone
To Rachel: screw off, goddamn bunny leech
To Platinum: screw off
To Jin: Not now Jin, goddamnit
To Taokaka: Hey Tao, wanna grab something to eat? :D