Great points, everyone.
I think most of my indifference to Isabel came from S3 (not a big fan of that Season in general or with the character) but if I had to pick seasons with her that I prefer her in using my 20/20 hindsight - I do like S1's set up and dimension the best, with her character development moving along into S2 as well. As others pointed out in their own words, she put off this superficial/snobbish exterior in the beginning; however, there was definitely more than meets the eye there. Another really good Liz/Isabel moment is when Liz is pretty intuitive and hits Isabel's issue right on the head: In
285 South, they're on the road trip and make that convenient store stop. Liz tries to break some more of the ice by bringing Isabel that coffee, I believe it was, but then they have that awkward moment where Isabel turns and the liquid contents go flying all over both of them.
Liz reassures her that she's not trying to take her brother away from her. Which I think is where Isabel's fears always truly lied: losing her brother and her family due to their secret being exposed. And Liz was that very real/believable 'threat' to her for a long time. Nice response back from Isabel, though, no words needed because Isabel kind of gives Liz her reassurance back when she dries Liz's clothes for her. Both were harboring their own fears regarding each other and I think a new foundation for them was set in that moment, even if they weren't going to be the best of friends at this point in time.
Oh, sorry, forgot to say before that you can add me.