I have watched SAO ,many times from start to finish and even bought the English translated LN available, also read Alicization up the translated volume online.
Spoiler for plot spoiler of SAO:
The Story revolved purely around Kirito and his experiences. It does have some deviation and goes into Asuna's POV in Season 2 Mother Rosario arc which was to me a little frustrating for me as I really enjoy the romance part of Kirito and Asuna and love to see them develop..
To me Season 1 was a love story between Kirito and Asuna showing How Kirito closed his heart early on due the the incidents that occurred (protecting the beta testers and taking on the role as villian, the blackcats of the fullmoon guild that got killed that he felt was his fault and so on) then Asuna breaks all those barriers rather forcefully and he slowly becomes human again, saving Silica, helping Lizbeth find her humanity .....
For me season 2 started off good and maintained the relationship of Kirito and Asuna, but it somehow felt they were starting to drift apart. Keep in mind in Season 1 Ancraid they got married and even had virtual sex and vowed to be together forever once they got out and kissed several times. The Fairy arc, Kirito committed himself and all he was to saving Asuna no matter what it took, I loved this arc alo as it had alot of feelings in it espeically when kirito' sister discovered his identity, that was probably the best scene of the entire series imo.
Season 2 it seems the romance went out the window, Kiroto and Asuna are no longer intimate, tho they do go on A date at the start of season 2, they sit together on the mushroom holding hands before he departs to GGO and she shows concern for him in his battle against Death gun.....but that was it, but the romance levels was not even close to season 1, it to me took a step backwards.
In Alicization.....great great story, but we take an even further step away from the romance.