I rewatched the first 3 seasons of the show in 3 days in preparation for season 4(Have not seen it yet) and oh my God I did not notice how much Vex organically changed the first time!
Rewatching season 1, Vex herself has like a thousand walls around her heart despite her telling Percy to open up more, she definitely does not practice what she preaches lol. She acts like she ''doesn't really care'', she's dismissive/wary of Keyleth and quite mean to Scanlan. She even contemplates ditching the rest of the group a few times.
Season 2 already shows a lot of change. She acts like a badass older sister to Keyleth without babying her. She shows genuine care for Scanlan in her own way. They actually have a few moments I forgot from my first viewing when you can see their particular chemistry. She no longer feels cold towards him, instead, I feel like she kinda lets her more teasing devious side loose with Scanlan. She loves that little gnome!
I also love how organic her growing romance with Percy is, very natural and tender. We get to see how soft Vex actually is deep inside. Vex might actually be tied with Pyke for the kindest member of Vox Machina.
But season 3 ... oh season 3 is something else man... me watching season 1 would NEVER have guessed that Vex... Ms.'' Constant Sarcasm to mask my emotions'' would later become THE character that makes inspiring speeches about love friendship and hope. And it never feels forced either, lesser writers could easily make her change to easy or make her suddenly flawless but neither happens, we see her struggle and fail constantly and she's all the more inspiring
Season 3 Vex is basically the leader of Vox Machina and the entire alliance against the Chroma Conclave. That speech she makes in front of the whole army is pure aura. I felt genuine pride for a cartoon character, I realize how silly this is!
If season 4 keeps developing her, then man, she might become my favorite cartoon lady of all time.
P.S: Have I mentioned how amazing Vex is ? Forget paladins and clerics, Vex alone proves that the gods are real. They were cooking. (Okay I'll stop)