@TARINunit9
Not quite…

She does think RD would be a good 'rough-and-tumble' type of sister, but Hasbro thought it wouldn't fit with the desired feeling of the show.
With two other established and accepted sister pairs, she just didn't bother fighting them on the point.

RD x Scoots is my favorite pairing, though, for these exact reasons.
I'm generally a sarcastic person so I like that kind of joke-teasing relationship.
The fact that they aren't sisters makes it even more special because there is nothing compelling them to like each other, like family ties.
They just genuinely enjoy each others' company.

Not to mention, they're just damn cute: