My whole stance on this is, whoever T'Challa gets with, she will have to be top-tier in the Marvel Universe for Marvel and fans to really care about her as queen of Wakanda or as his love interest.
I say this because sure T'Challa could get another love interest without too much trouble, but exactly how important will she be to the overall Marvel Universe in-story? Monica Lynne isn't all that important to the grand scheme of things, and neither is Monica Rambeau when you really think about it. Monica Rambeau has been placed into comic limbo before, as has Monica Lynne and any other romantic interest that T'Challa has ever had.
And I know there are numerous people who like Black Swan and want T'Challa to hook up with her, but my thoughts on that are, other than Jonathan Hickman, who is using her right now? After Hickman is done with "New Avengers," will he write Black Swan being an important Marvel Universe character in any other Marvel book? Will other writers use Black Swan in any other books after Hickman is done with "New Avengers?" In 2016, 2017, etc. will she be placed into limbo, or will Marvel promote her as a character? How important will she be as a character to Marvel at that point, when the Incursion story line is over? How important is she, really? Marvel seems to be more interested in Angela (a character from another comic book company/universe) than Black Swan.
God forbid that T'Challa ever go back into limbo, but if he did, any love interest he would currently have would go into limbo right along with him, as would Wakanda. That's why if he had a high profile queen or love interest, she potentially WOULDN'T go into limbo, even if HE or Wakanda did.
To me, that's one of the things Storm brought to the table. If the writers and editors had actually acted professionally and acted like adults in writing the royal couple instead of having them break up over some poorly written B.S. that made no logical sense whatsoever, Storm could have still represented Wakanda on the world stage, even if for some reason Black Panther and Wakanda were placed into limbo or weren't used in books that much. We still could have kept up with Wakandan events through Storm, since she is in several books right now (although her portrayal in some of those books is questionable at the moment). Storm, WHEN WRITTEN CORRECTLY AND WITHOUT ALL OF THE EDITORIAL AND WRITER HATERADE, brings so much to the table it's absolutely ridiculous. She's popular in-universe and outside-of-universe (cosplay, the general public knows who she is due to the X-Men movies), instantly recognizable, won't be placed into limbo ANY time soon, has been around since 1975 and is one of the most powerful mutants in the 616 universe. If she had remained queen of Wakanda, people would have learned more about Wakanda through her (if Black Panther wasn't appearing anywhere).
When I think of things like this, like Black Panther's love interests, I like to think of the long-term ramifications of these unions.