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.
I'll definitely agree that Erika Hernandez carried those books. But the story was great on so many other levels that you can almost ignore that the Caeliar were pretty much a deus ex machina. I fondly recall how Geordi told Picard where to go and how to get there when he wanted to build a thalarion weapon for example. Garak's interactions were awesome(politics suits him), Bacco's character was interesting. Even Necheyev and Jellico had an interesting dynamic. And the stakes were much higher. I liked Inyx's definition of love too... "she makes eternity worth contemplating." I did literally shout when I realized where the Mantillis survivor story was going. Even if yeah... humanity is at the center of EVERYTHING in the Trek universe.
All the Titan crap and the OMG BABIEZ angst was godawful. I would have loved just the Erika Hernandez story as a stand alone, not constantly interrupted by seemingly ever other Trek character ever.
Yes, this was the worst part of the books, Troi had a high risk pregnancy, there was no way I could suspend my disbelief enough to let her be on that away mission. And IMHO the doctor that allowed her to go was a quack. That just didn't work at all for me. I know Mack was trying to give the books tension, and suspense, but he should have found another way.