I was too in love with Fenris to want anyone else! Although I was not able to on my first playthrough (the rivalry/friendship system weighted everything the same and I felt a rivalmance made sense with a pro-mage character but I was not going to gain rivalry points by treating him or slaves poorly ). Anyway, on that first playthrough, Anders stole my heart with that kiss... but then broke it in the end....
Oh, but who else would I wish to romance? Varric is certainly appealing in both DA2 and DAI although in DA2, it felt right for neither him nor Aveline to be interested since so many other characters were fighting for Hawke -- it would have been too much!
Cullen certainly gained further appeal in DA2, but illogic of him talking to my mage Hawke as if he were not one, even after fighting side-by-side was... distracting... I can imagine Hawke entered the Gallows incognito, but certainly he couldn't hide his magic in a fight.
So really, I guess rather than making another character romanceable, I would have wished fixes in the system that was.
But Feynriel... once he is older... mmm, I would hope that he at least appears in a future installment, but perhaps that is not possible considering his many alternate fates... although setting off for Tevinter is canon in my book!