I think they should (based on what I've read with the fan desires and interests and overall style present) have like a kind of focus on making more of the "cute, advisory" characters, male as well as female LIs for a kind of alpha focused male/female Shepard, sort of like Josephine or Kelly Chambers not central in the same way as some characters.
It's not that they "literally don't have a role" but simply that they follow in that sort of format.
I think in general having characters that are kind of disinterested from the main of quests and such in ME would not be a bad thing in this case and in fact better fit the kind of overall dynamic I see present in ME games. Moreover, I think it stems from a style of game that goes all the way back to the origins of the company as a sort of back and forth between two kinds of competing personalities a bit.
In many ways, it's basically just asking for more "Samantha Traynor/Kelly Chambers/Josephine" like characters, male and female. I don't really think Cullen fit that dynamic because he was less of an advisory type and more an active commander who just happened not to be commanding.
That dynamic, to be more clear, is I think one where the partner is generally kind of the (well, at least perceived as) "purer" contrast to the kind of reckless get stuff done Shepard or main leader, there isn't as much overlap between their interests and desires. That isn't to say they aren't interested in each other, but rather that they come to each other from kind of "opposing worlds" so to speak.
More often than not, that character has been female, but I think it could be male as well, and I think in general, both kinds of "advisory" characters reflect a desire on the part of the Bioware fanbase and developers. Moreover, there are other media which represent opposing dynamics and thus would be perhaps a better reflection of their desires and interests.
Ahem, anyway, I think one important thing is that certainly isn't the only dynamic present in media, which is why then it's probably ok for Bioware to give this option since it seems to me to be where their interests are and have centered around those things through their history, as well as the kinds of things they are looking for in games.... whereas other games/media present their own perspectives which is more appealing to people who want the different things and that's ok as well.
I think personally as stated I've kind of found the notion of "romance" in a lot of media in general not typically the kind of thing I'm looking for, regardless of it's precise dynamics, but I think if developers/fans are creating/getting a thing that is meaningful to them that is a valuable thing there, and it's not as though I don't find it.. well it's something one it's own for sure. I still watch movies with romantic elements and shades of various kinds.