For being the last line of the original Bionicle series, Bionicle Stars was kind of a letdown. I mean yeah, it was sorta cool to see Rahkshi, Piraka and classic Tahu again, but the sets themselves were a major downgrade in articulation. They were basically sending off the series with a line of Matoran. Also, the pieces were kinda more fragile than usual, IIRC.

Kaitas are just a way of making weak Toa stronger!