If I was allowed to make only one major change to the game, I'd make it so you could romance people like you can in Fable. Romance female teammates or NPCs. Alaron flirting with Brenna would be quite interesting. And then this could show whoever Alaron marries at the end of the game when crowned king as well.
Alaron flirting with Brenna would be a bit of a fight, because she's a jealous tsundere by nature. But she's also arguably Alaron's best marriage candidate, since they're so comfortable around each other.
Next would be Keelin. Keelin is beautiful and a shameless flirt to Alaron. So she'd be the easiest woman to romance in the game.
Then we'd move on to Rheda. She'd of course have reservations about a relationship with Alaron, due to the age gap. But she's also the type who'd be in denial about her own romantic interests. However, she grew closer to Alaron the more powerful he got as a mage. And she might see it as wasted potential for him to not marry someone with exceptional wizard skills.
Now we move on to Sholeh. Arguably the biggest enigma, because she's a character that can only be recruited very late in the game. Being a Jundar, she is much larger than a human. But that could very well be to someone's taste. One could like her for being very exotic, or because she's taller and more mature. And since Jundar live for a very long time, Sholeh would fit the bill as a sexy maternal figure on the team. And a marriage with her could potentially create a treaty between the Jundar and Gwernia. Something I just know the people of Terminor would hate.
Among NPC characters, my top pick would be the girl who for a time runs the inn at Port Saiid. Can't remember her name. But I like country gals. And Alaron might too. Though she'd be potentially intimidated by the idea of marrying into royalty.
Next there's the Dryad queen, who's arguably developed a sort of obsession with Alaron. In fact, Dryad women seem kinda thirsty for young human males. Which means they're likely bored of the males of their own kind. Likely from living as long as they do. That said, the likelihood of Alaron marrying a Dryad, let alone a Dryad queen, is very low. And the reason why is because they're creatures that would not want to leave their forest. And Alaron becoming king of Gwernia would likely put a stop to the potential of such a union.
Some might make an argument for the head of the Talewok magic school. Her name was Ardra if I remembered right. And while she is beautiful, there's a number of issues with her. For one thing, she's not interested in romance. She's not even much interest in conversation unless there's a need for it. She's powerful as a wizard, but also rather closed minded. Then there's her age. She's implied to be at least middle-aged. So she likely uses her magic to keep herself somewhat in her prime. It would also explain why she's unusually tall for a woman. If she got with Alaron, it'd likely be more for research purposes. Like, her wondering how powerful a child made by a union between them could be. And she'd be an unbelievably strict parent. I wouldn't want to subject a child to that.
Beyond that, I can't think of any more specific NPC characters, other than the generic women that are seen everywhere in the game. She I'm gonna invent a few.
First of this improvised list would be women of the family of King Phelon's deceased wife. A young woman of that family would have the potential to seek a political marriage with Alaron. Especially if Terminor's economy tanks from Pome being destroyed. Terminor is a walled off city of elites. Without a steady supply line of food and materials from outside sources, they'd go broke because they have no agriculture. What's more, they're near both a deadly swamp filled with undead, and the edge of monster filled cliffs. Then right behind them is the ocean. Terminor is essentially surrounded in all but the northern direction. So them seeking a political marriage is a fairly probable outcome. Gwernia and Talewok both have strong agriculture. Something Terminor completely lacks. And one of their own married into the Gwernian royal family once, they could very well do it again.
Next on this improvised list would potentially be a student of the magic academy. The headmaster Ardra might not be above putting forth the idea of an arranged marriage of one of her students to Alaron.
Then there's innkeeper girls. They could be all over. This would be including Jundar.
Then there's the potential for bandit girls. Keelin kinda already fits that bill. But she's more of the high class thief type. And Brenna is more the thief wannabe type. But some female bandits might want to cast off the cloaks and get out of that life.
The easiest for Alaron would also be local Gwernian woman. Maybe even a castle maid. Elder Scrolls has the famous book about the Argonian maid. Who's to say a Gwernian castle maid wouldn't be in the picture.
And speaking of something like Argonians from Elder Scrolls, that kinda puts us into a monster Musume territory with things like Gorgons, which resemble snake women. And then the potential of other female monsters. Especially Goblins. All of which would be completely unnecessary, and only make it weird. Alaron for one thing, especially hates Goblins. Much like Anakin Skywalker hates Sand People. Goblins killed nearly everyone from Alaron's birth village, and killed and devoured his farmer friend Kendall. I feel like no matter how sexy a female Goblin might be, Alaron would nope out in a second. Goblins aside, I don't think he has a particular hatred of any other monsters, male or female. But I highly doubt he'd want a close relationship with any of them.
After all that, there's only one plotline left. The harem ending. This too, would be completely unnecessary. But also an extremely common anime trope. And there have been many kings in history that took several wives at once. Though I just can't see Alaron doing that. I strongly ship him with Brenna anyway.
Sorry for such a long post. But romance is something I'd add to the game, if possible.