Imo, Hikari's lyrics are just as bad as Simple and Clean's. Neither of them even remotely relate to Kingdom Hearts, which, weren't the songs specifically written for the game?
If anything, I think Hikari's lyrics are
worse, because they start off really poetic and then suddenly switch tone to something about TVs and family introductions. O_o At least Simple and Clean is consistent throughout.
I love Simple and Clean. It's possibly my favorite song by her. Hikari doesn't really do anything for me.