A couple of things I definately agree with here, and some suggestions...
1. If you have someone on staff who is interested in writing romances, by all means let them write the plots and dialogue, or find someone with an interest and talent for it to do it.
2. Gratuitous sex isn't needed. If there is to be such a moment in a tale, do it in such a way that it is not the most important moment in the relationship, but a new beginning instead.
3. Continue the romance afterwards, rather than allow the confession of love to be the end of the romance tale and come off more like a completed checklist item for a quest. Confessed love can lead to additional friction or concerns between the involved characters and can lead to all new lines of dialogue exchanges.
4. When including conflict in a romance, give the character opportunities to make up for their own mistakes, rather than leave it up to the NPC. Don't allow the dialogue options to simply end a romance with a single selection by the character, without later giving the character a chance to redeem his or her self and make ammends. Romance shouldn't be a dead end.
Of course, these are just my suggestions I mean