I think everyone is talking about ballad but giving to the word different meanings. For exemple I wouldn't consider the next LOVE a ballad. And a lot of people here is talking about ballads as "everything is slower then a rock song".
I'm not sure on what is the precise definition of ballad but for exemple for me even LOVE again have a reasonable number of ballad. On 15 tracks, I would consider real ballad just Ivy, untitled for her story 2, SAKURA and Sweet Scar (and maybe Gloria). Melody and petal for me are mid-tempo jpop songs, not ballad. The rest is defenitely not ballad at all. So it would be 5 on 15 (7 on 15 if we consider Melody and petal, still less then half), I think is an ok number. With Colours I would says just Angel and Pray. The other "slower" songs (What is forever love?, Merry-Go-Round and Hello new me) are midtempo pop song.
For A ONE we have three from the single + The GIFT and Story that is sort of an half (expecially if we consider Last Minute both rock and ballad) but for now we have still 2 unveiled songs.
All of this to say that I can't really see this overflow of ballad in Ayu's last albums. It's still less then the half and in this group of ballad there are a lot of different style (Sweet Scar, SAKURA and Angel are totally different as songs).
But maybe is just beacuse I don't really know what makes a ballad a ballad.
