First of all, I need to say I like the current model of Jaina. Just dropping a suggestion in.
Now that she is the Lord Admiral of Kul Tiras, I think she should change colours to reflect that. Put some greens in there to show her newfound leadership and representation of her homeland. On the other hand I see why she is wearing blue now to symbolise she is fully Alliance now and has pretty much dropped the Kirin Tor representation.
Does anyone agree with me?
Discuss 
her father is not even green in the reforge though his blue and red even flashback version of her father is wearing a blue coat
Hahaha…Daelin in blue and red…
what…he probably just wanted to unite the Alliance and Horde even back then? 
Slight correction, cloak and shoulders seem to change with his team colours in reforged. His mantle is blue.
https://wow.zamimg.com/uploads/screenshots/normal/876219.jpg
https://wow.zamimg.com/uploads/screenshots/normal/876256.jpg
Blue is better although it should be green…
but it probably depends by which colour the player picks for his/her unity, probably
I don’t dislike it too much, because if you look at my heritage armor or at Daelin, they also have a lot of blue and gold on their robes. Maybe she could change the color of her staff to green but I don’t really think she doesn’t represent Kul Tiras with those vests.
Daelin was already depicted without green in his official art in the TCG, so way before Reforged:
https://gamepedia.cursecdn.com/wowpedia/2/2c/Daelin_TCG.jpg
https ://66.media.tumblr.com/797189d2666fdc3b0104379d905da922/tumblr_inline_pdm04g9tLb1sfspf7_540.jpg
no green there
Katherine also barely has any green for that matter. Like she has some green on the inside of her jacket, but that’s it. She has a lot of gold though.
https://wow.zamimg.com/uploads/screenshots/normal/749677-katherine-proudmoore.jpg
I think the blue and gold is generally preferable for a few reasons.
As others have pointed out, both Daelin and Katherine set a precedent for going with very little, if any, green in their outfits. If you consider “gold and blue” to be Alliance colours, you could also argue that Jaina represents the Alliance as a whole, both on Kul Tiras and abroad.
That said, the dark ocean blue she wears is more representative of Kul Tiras than the Alliance, which usually favours bright and heavily saturated blue and untarnished gold to the more corroded copper/bronze color of her metallic accents.
It is worth pointing out as well that the vibrant sea-green is not just the colours of Kul Tiras but specifcally the colours of House Proudmoore. Wearing all-green might be more traditional and insular, which Jaina certainly is not.
I’m inclined to agree with your post, but allow me to play the devil’s advocate. I’ll make a comparison between Jaina and Thrall, who’s sort of a foil for her on the opposite side. His most recent iterate features these hair pins for his braids which are blue and silver - the color of the Frostwolf Clan. It’s subtle, but it’s there, and he isn’t wearing any black or red.
Since Jaina is arguably not insular - we could perhaps argue that she’s now a world mage, too independent for even the Kirin Tor but believing in Azeroth as a whole - could we suggest that she drop any blue and gold and perhaps retain a bit of the House Proudmoore colors, but in a very subtle manner?
Not all important characters wear the national colours that belong to them, anyway.
For example Halduron Brightwing Ranger-General of Quel’thalas wears all blue like he was an High Elf, and not the traditional red + gold (or black) of the Blood Elves. Same for a lot of others
It makes more sense that Daelin and Jaina wore blue and gold over green. They represent an age where Kul Tiras stands proudly with the Alliance, while Katherine (who definitely wears more green) represents a period of stagnation and isolation where Kul Tiras is alone and too proud to side with the Alliance.
Also, Jaina could be donning a blue and white robe in memory of Theramore, which symbol was a blue anchor on a white field.
I agree that blue is a good symbolism for alliance togetherness. But Kul Tirans wear green, they always worn green. Daelin’s old WC3 model had green and the faction tabard is green. Even old Kul Tiras Marine models in Durator had green gear.
Actually Daelin’s old model still wore blue and golden robes. His cloak and pauldrons were dark green because that was the color of the Kul Tiran faction in Warcraft III. It will be like that in Reforged too.
https://vignette.wikia.nocookie.net/wowwiki/images/7/76/Proudmoore2.jpg/revision/latest?cb=20090817154821
yes but it has green 
what I’m saying is put some green on Jaina as it is the faction colour haha
I have a theory Jaina was modelled after a 1990’s pornstar called Jenna Jameson. 
Don’t forget to mention that instead of libraries she was hiting dalaran gym 24/7.
As one friend from forum noticed she needs one her quotes to be changed to “All i ever wanted is to lift”
I think that they should give her the playable Kul Tiran model to make her more identifiable with that culture and race.
Don’t be jealous that a 18 years old human has a better physique than a 10.000 years old smurf.
https://wow.zamimg.com/uploads/screenshots/normal/878063.jpg
Look at dem abs. She puts the WoW night elves to shame.