Ok, here's a summary of Arnel's Nalia romance. This is full of spoilers so do NOT read if you do not want to know how it goes. It will probably ruin your Arnel mod experience if you read this, so be forewarned.
Realize that it doesnt really start until you do both the keep invasion quest and then finish off the slavers in both the Copper Coronet and the slaver's ship, and give the slave girl in the troll pens 100 gp to get home. For most of the dialogues there is some unique music you never heard before. Obviously, there is no voice over of any of the new lines and Arnel's romance does NOT carry over to TOB. His website has not been updated in nearly 2 years and there are no indications that a TOB patch will be made. His website is a German server, fyi.
I've read complaints on other boards is that its heavy on Nalia flouting her helping the poor idea, to the point of being revolutionary and silly, but if you read most of the dialogues in the non-modded version, she is REALLY like that. The dialogues in the mod follow this idea nicely where she is consulting and getting ideas from the PC (player character) about how to accomplish this best, and the conclusion reached is to do it on a large scale, politically. Her eventual goal of joining the Council of Six to accomplish this is discussed and also follows her TOB ending pretty well. There are some spelling errors as well, but they were minor.
There is one dialogue after the keep invasion where you get to say a line or two to comfort Nalia over her father's death, but its pretty short. When Nalia is called to her father's funeral, she meets up with Isaea, and then decides that her original plan is not fooling anyone, b/c of Isaea's reaction. She asks the PC to agree to a marriage of convenience. The whole party is whisked back to Nalia's keep where they are married in a small ceremony with Minsc as the best man, and which includes the party, the major domo, a priest of Tyr, and about 3 other keep workers. Its kinda cute when the priest asks everyone "should their ways run together?", and everyone goes "Aye". The wedding is notable for a "blessing" from Tyr.
During the dinner celebration, Isaea storms into the dinner hall with his Amnish army guards and kidnaps Nalia, like her abduction in the un-modded version, and with the same rescue quest. After her rescue, out of desperation, Nalia offers to consummate the marriage to put to rest any doubt that others have as to whether they are married or not. I believe the only correct answer was to decline.
The other romance dialogues were pretty much what you would expect; the PC making nice dialogue choices and getting a nice response from Nalia, especially if you give her good advice and ideas to help her accomplish her goals. Many dialogues are "helping the poor" related dialogues which helped to flesh out Nalia's views and that was fine. There are also some dialogues where Nalia and the PC ask about each other's parents and how they influenced their lives. I simply thought there werent nearly enough of these "getting to know you" type of dialogues, but that was my opinion.
Arnel's mod also includes a side quest which involves a childhood love of Nalia named Joseph Armenthorp who is hiding out somewhere, and involving his traitorous ex-business partner living in Trademeet. Eventually Joseph gets ambushed after meeting the PC and Nalia, by his ex-partner's goons, and a dying Joseph asks you to look after Nalia.
There is an attempt to link the Guarded Complex in the Temple district with Isaea, and Nalia suggests they go there to look for more evidence. In the Guarded Complex, one of the goons you meet early admits Isaea's involvement with their organization and the keep invasion and you find your usual document implicating the Twisted Rune House.
You can finally get evidence to put Isaea away in the Twisted Rune House in the Bridge district. After you deliver the final evidence showing Isaea's involvement in the keep invasion and slavery to Inspector Brega, Isaea is summoned, admits involvement, and he is taken away. At this point, out of frustration, Nalia offers to consummate the marriage to put to rest any doubt that others have as to whether they are married or not. I believe the only way out of that was to decline.
Somehow he gets away again and shows up to challenge the main character to a duel. Its a trap however; as soon as he starts losing, some goons show up to try to kill the PC. After the fight, the party chases him back to his Govt. district home, where another fight ensues with Isaea and 2 mages. Isaea is subdued and taken to Brega again where he resists yet again and is killed for good by the Cowled wizards. Not long after this episode, after one or two dialogues, Nalia suddenly turns aggressive and wants to see what the PC looks like "under all his clothes" and you know what happens.
The rest of the mod is pretty much as Arnel suggests it is, involving Nalia's abduction by Bodhi and the PC having to restore Nalia, with a touching line after she is restored. There are some other notable dialogues including an addition to the Tree-of-Life dialogue which involves ONE line from Nalia to the PC, before the party enters the final Tree area. Except for those 2 situations and one or two others not mentioned before, Nalia says precious little romance-wise for the rest of SOA.
Overall I thought this was a well done mod for the very short amount of time it was in development; I just wished it was a bit more developed, especially the romance dialogues. I never really felt the PC or Nalia formed much of an romantic attachment for each other before they slept together. I was impressed with the effort put forth on the childhood love subquest, but was unsure what purpose it served other than to give Nalia a little more background and also to give the PC a reason to take care of Nalia.