I loved Destiny for the first one, the Erika Hernandez story. I remember getting teary during it.
I think Erika Hernandez was the very best thing about those books, and the sad thing is that using the same plot lines with just a little more tweaking, she could have been the catalyst that solved the problems of the plot line. She had great character growth, but the only Caeliar to show the same growth was Inyx. Her interactions with the Caeliar could have provided that same character growth for the rest of Axion's Caeliar, in much the same way that Caeliar/Human interaction changed the Mantilis Caeliar.
All those books were Erika's story and not anyone else's.