Riya seems to be more or less like Kelt.
Obnoxious... but you still keep coming.
I think the "problem" with Riya is that there's no "fodder" characters to interact. I mean, this is not a RPGmaker game in which you see dozens of little guys running around saying "Hi", "Bye" etc, and you encounter one that says "let's fuck", then you have the more complex characters, and then the recruitable -or not-NPCs.
So she kind of sticks outs in TiTs and appears to be a less-developed character (which is not really the case. It has a different set-up, instead of the usual super-developed character)
For example, if there were an USG officer on each location, with the same type of "build" (small talk, less developed scenes, etc), but different personalities, she wouldn't be so notorious. Or let's say, some people walking around, or a technician (like the ausar guy at the very beginning), etc.
Personally, I don't have a problem. Actually like the simple approach, and if there were 10 more characters like her added, the better. If she gets more content, the better-est.