So, I played Vesiana as a Theramore inhabitant for a bit. Been a long time. She was a Dalaran refugee that basically got adopted and trained there before returning to New Dalaran.
Theramore was primarily founded by refugees from Lordaeron and Dalaran, with a healthy Kul Tiran influence (some from Jaina herself, the rest from Daelin Proudmoore’s expedition). The culture was essentially a mix, with a huge refugee mentality combined with a largely seaport atmosphere.
Things got tense with Daelin and his crusade against the Horde. Jaina felt it was her duty to kill her father (or rather let him be killed) so that the war could end and there would be peace. Some of her father’s men were understandably upset by what happened and began a mutiny, that ultimately was exposed by Onyxia and the Defias by the time of WoW.
The refugees from Dalaran were notable for founding a new Mage School at Theramore. It had several trainers, including a portal trainer, and they sold unique equipment and reagants.
Theramore was also the primary Alliance hub in Southern Kalimdor (arguably all of Kalimdor), since so many quests and zone progression ultimately led there. I believe, if I recall correctly, it was also where most Alliance folks ended up for their lv 30 (or 40?) class quests. Also a mount vendor!