You know...the fact that you put Hurricane Venus and Only One in the same category (of r&b of all things) is very telling.
Or perhaps it's that you've compared Only One and Hurricane Venus to Janet.
Or that you think Rhythm Nation is a late 90s-early 2000s sound. haha.
BoA has had Janet sounding songs....but it surely isn't Hurricane Venus or Only One.
No Dance No Life pretty much has Janet written all over it. I think it's even a sample.
Anyway I think BoA can be any type of artist she wants. She has planted the seeds to really go in any direction she wants (from r&b to electro to jazz, etc). It's really just a matter of making that effort to create a cohesive body of work.
No I'm not saying Only One or Hurricane Venus sounds like Janet. Nor am I saying Rhythm Nation is late 90's or early 2000's. But BoA is obviously a highly technical dance artist who more or less is trying to follow the footsteps of Janet Jackson, like all female dancing artists, which isn't a bad thing, its a good thing that she's an excellent dancer.
BoA suffers the same syndrome as Koda Kumi, the "I can do all sorts of genre but I don't really master any of it" syndrome. Except Koda Kumi has the slutty, sexy and fierce image with a heavy rock sound to fall back on, which she is well-known for. BoA is just that singer that's good at dancing with overall okay-sounding songs, people don't associate her with any sort of sound or image. The closest is R&B-influence but it isn't doing BoA any favors, both in Korea and Japan. The R&B style BoA does is pretty early 2000's and late 90's style. My siblings who grew up listening to R&B and Hip-Hop in the 90's tell me BoA's "R&B-esque" songs such as Only One for example sound rather outdated or very 90's.
Overall I guess you can say BoA still has no clear definate image or sound people associate her with, which makes her easily forgettable. There isn't really anything iconic about BoA... she has yet to create an icon of herself. I feel BoA needs to have an era where she clearly defines her image and sound, because right now she's spreading herself too thin doing Rock then R&B then Dance, and none of them are really memorable. This is also a reflection of her career, she has no focus anymore. After she stopped focusing in Japan, after her failed American debut and now her average career in South Korea, where does BoA stand really? Ready for retirement? Oh how the mighty BoA have fallen...