I'm so far interested in the Shadowheart, Astarion and Laezel and possibly Minthara.
Shadowheart provides that challenge to open up a cagey character type path, even if a cliche choice. Plus the VA does a good job at portraying a transparent coyness used as a defense mechanism.

Astarion, I love. He uses flirtations and words as a defense and tool, but is also just about getting as much amusement out of situations as he can (can relate)-We were definitely thinking the same thing about the resolution of the hag quest and getting that wand. But he also suffers from the doubt/anxiety of Cazador's reach.

Laezel, honestly just because its funny the lines you get from her when you romance her and I am curious where that goes and the dynamics of it playing out.

Minthara, There is not a lot interesting about her yet in EA. If you lay with her after taking the goblin side of the grove assault there is an option to try to look into her mind and learn more about her, possible character development in that area when/if she is encountered later is of interest.

Gale, charming words but his plight regarding his background is less intriguing to me.
Wyll, I will help him get his demon lady back, but possibility of heartfelt discussions about caring for a demon or the nature of the allure of power or whatever he might entail after his wall of bravado is brought down kinda not very interesting.