I don't know if they will add more to the main plot, but there WERE some gifs I remember (Now gone from the internet because of Fujino purging his content before escaping China) that were never implemented in the game, at least one was of Asuna's mom fucking one of her fuckboys in a shower, so it could be putting those in the game somehow. Alternatively, it could be just adding H-scenes to parts that 'should' have had them but didn't, like maybe during the final day while Kirito is going around town reminiscing the scenes were the ugly fatso is having a threesome with those 2 girls or where Hebishima is fucking Suguha behind the cafe now have animated CGs?