Was her romance not popular with females? I'm honestly curious.
To me it was very very lacking. I liked Liara, romanced her in one, was true to her in 2, and romanced her in 3. My gf romanced Garrus and the incredible difference to see those side by side was ridiculous. Regardless of that, she lacked a lot of oomph and was a little too empty of any passion with the relationship. (Not saying they didnt have their intrests, but I liked the relationship more of Leliana and Marjoline without the obvious bit of the backstabbing)
Leliana was similiar, lacked a lot of passion in regards to the romance, sweet, but I have sch a hard time putting my finger on it. Liara and Leliana seemed very passive characters, especially Liara who seemed like more of a plot device in 1. Sam, on the other hand an unimportant character, was actually fine, but Leliana and Liara seemed more backdrops. Jacob felt similiar in some ways. He seemed fairly passive not so much as a personality as a character.
I do think that (kinda)Tali, Liara, Leliana(there is a reason she is the most romanced), Merrill, are made somewhat passively and that appeals to straight male gamers. I am not saying that they did not have needs or intrests or goals, but they took a more back seat to their own story.
Women on the other hand always seem to lean towards more active characters. Garrus, (a reason many ladies wanted Wrex), Thane(except at the end), Alistair, Zevran. Anders, (kinda)Fenris. Varric
Jacob and Kaiden are fairly passive and my theory is that is why they are disliked more in the fandom. Many lesbians I have seen show a preference for active characters- Jack, Miranda, Morrigan, Isabela, Ashley, and from the looks of it Cassandra.
Not saying so much for the forcefulness as Alistair actually hates to do anything and is fairly passive personality wise.
I dont see it as a sexist thing, I just always felt that straight men like passive usually more then women, and women usually prefer active types.