I love drama in a character's story, it makes the romance more involved with the plot. The problem with Fenris and Anders drama though is they were fanatical on each side, and it is really hard to empathize with any fanatic. Many people are calling Cullen as a romance and I agree, because in the past, his drama suits well with the story. He was attacked at the tower, and hated mages, but still came to their defense a little in Dragon Age 2. Conflicted. And a person on either side of the debate can swerve his beliefs.
One reason I loved Garrus, and wanted to Romance him since the first game, was he was a little bit a protege, in a way you guide his beliefs, which shows how he reacts to you in his sidequest in 2 and he is a Shepard to the Turians in 3. Befriending him or not there is a story there.
Jack was a great romance for the same reason, the relationship seems to change and you help them grow as characters, OR they help you. Jack was a character with her own goals, own values, and romancing her was helping her character and let you see insight. Zevran is a bit like this, and in a way so is Leliana and Alistair, but less so. You can harden them or make them face their past, but after that it runs out of smoke.
Garrus has no past but he seems to grow with the relationship, and Jack is the best romance I think Bioware ever put out. Anders and Fenris had issues but they had nothing to do but hate each other and be fanatical. Both had reasons to be, but so hard to empathize. Merrill had one, but it also was fanatical and she seemed oblivious to any romance til the end when it was either be cruel to her or sleep with her. Isabela was a great idea but she had a sad past that didnt mean anything. Over ten years none of them changed, on their own or with you. It seemed so lacking as a romance. They dont have to be better or more like you, they can be more antagonistic, which is why I love friendship/rivalry but they certainly dont need to be so static that even fellow characters find it annoying. 10 years is a long time, but each was as fanatical about their goals as everyone else.
I would have loved for Merrill and Hawke to have a romantic scene beforehand, and show that Merrill questions it more with a rivalry or even do the quest anyway by a fellow elf but convince her out of it and she could see her folly, or keep it and show she has something to her character than just the eluvian and being Dalish. Or make the Dalish parts of her more pronounced in a romance. Like courting in a Dalish way, or even wondering and comparing her life without a cluless steak of not knowing when someone was attacked, as someone who goes out with Hawke it seemed strange she didnt know that being mugged is bad.
Fenris was great in his off moments, and there was something with his memories and the silver. More about his old life, or trying to settle, but every conversation had at least one thing about denarius. He had good reason, but it felt so pale when it was the only thing that defined him.
Anders is such a fanatic he blows up a building and his personality gets rewritten. Such is fine, but something more than just pro mage stuff every sentance. It was hard.
Sebastian wasnt so bad, he was for the Maker, but he was pulled between two sides, and pretty relaxed overall. By far my favorite romance.
Isabela was alright but once again her life was more a caricature than a real person. My second favorite due to her fun nature and at least not being overly obsessed with something.
As for me; my favorite romance would be someone with their own problems but ones that dont define them. Anger issues, dethroned, disinherited for good reason from a non noble family, Too Prideful like Nathaniel not Vellana, Lost siblings, Getting an important position, easily possessed by spirits, guardian over an important item. And other character traits that have nothing to do with it. Like- bad at jokes but tries anyway, family person, easily depressed (but not about their problem alone like Anders and Fenris), religious, can't get them down, someone who enjoys politics, poor as dirt, rich as kings, rude, too polite, kind, anything really, if their traits war with each other all the better, which is what I hope Cullen will be. Someone who wants everyone saved or everyone dead isnt nearly as fun as some need to die, but these people don't deserve it.
I would like a pro Templar Mage who worries because they are easily possessed and rely on the templars protection from blood magic, OR a pro Mage Templar who realizes that they might have killed out of hand and bears it as a mark against themselves. Ones you can influence in either direction for good or ill. Protect the Pro Templar and make them realize that they need to be strong for themselves, or teach them that with their help they can build a less oppressive circle that benefits the mages for their protection. Pretty American.
Or show the pro mage that guilt should not lead their lives, and that they did it for the greater good, show mercy to those who have a great burden, but do not let them take over and let power best them. OR let their mercy create an age that will free the mages of burden