IIRC, wasnt her the first that seem to love Kazama? Then she started to become more a gag character.
Roka's love was always a gag, if you go by Kazuma's reaction to it.
Roka's moe element plays on Kazuma sadly gets as a little consideration from him as Tama-chan-senpai's direct flirty advances.
Takao probably would be a gag love interest too (or not even in the story anymore) but she has two big reasons to be popular and the author couldn't ignore them either.
Takao's personality and the stuff that happens around Takao tends to be interesting, so it's not a loss imo.
I actually enjoy reading the Takao family volume extras.
Usually Roka would win in the end ( if this series was ever going to end instead of being a somewhat low effort money source for the author to doodle with) but Takao got VERY popular very quickly and very early in the series - so unless the author wants to risk serious backlash if he ever decides he wants to write a new series that he's passionate about:
The D-FRAG ending will have to be an (implied) open harem, Takao win, Takao+Roka win, or nobody wins but the adventure continues (but the last few scenes imply that the current favorites are still in the lead)!
Desuno is kind of annoying, but I wouldn't mind her stealing Kazuma out of no where.
But it's not my career that would be ruined by that.
A Tama-chan-senpai win would be pretty amazing too, I liked her flashback chapters and her 'crazy bitch aura' is impressive.