It's been so long but I don't think they were terribly written. I mean the characters are trash and Bella is a dumb bitch, but I wasn't frustrated enough to actually stop reading. I've only put down one book for good so maybe I'm not the best measure to judge by, though.
I guess this is an unpopular opinion, but I liked Xenocide. It's a good book. Oh, of course it's not anywhere near the level of Ender's Game and Speaker for the Dead, but I enjoyed it. Ending was a bit weird and that's why I didn't start a sequel yet.
Maybe it helps that I listened to audio book and didn't read the physical book. Some books are more digestible in audio form imo.
Or, because I go through 120 plus books in a year, my picture of a terrible book is different.
I think most people agree that Ender's Game and Xenocide are some of his best works, largely because they promote messages his dumbass doesn't realize his own beliefs violate.
My biggest issue was the deus ex machina solution. Oh cool, you can magically do whatever you want as long as you imagine it hard enough, and oh look ender has a magical super ai because he's ender goddamn main character syndrome wiggin. Literally every plot line solved.
Also ender is a pretty terrible character. Probably as bad as Bella, even.
Read it in my early 20s, as a guy. So, not the target audience.
It wasn't bad. To be honest, the secondary characters were so much more interesting. Edwards family in particular were often deeply written, compelling, and downright fucking cool sometimes. Edward is super brooding, Bella is a cardboard cut out designed to filled with the reader, and Jacob was honestly pretty compelling, but a little overly emotional. All in all, decent books. Like 7/10