If they like someone, that's a good reason.
If the character already has a role in the story which is NOT one of a "companion", then there's no "good reason" to ask to make it one, if not the usual misunderstanding that this is supposed to be some sort of dating sim.
Sarevok ... Loghain ... The role of a character in a story can change for a variety of reasons, assuming the storyteller to be reasonably imaginative. That you can think of only one reason to request such a change is a statement about you, which says nothing about any other poster or the impacts, positive or negative, of making a particular character a full companion. Halsin contrasts strongly with the self-centered, patron-reliant males currently available to join the party. Whether he would be romanceable or play a more Keldorn-like role in the group, I'd welcome his company on the road.
