Hmm. My DD is in second, and her teacher (IMO) is expecting a lot in terms of writing assignments, but she has also struggled with them. It's not because she can't write quite beautifully, but because having to work with a structure and a set topic not of her choosing is new to her. I wouldn't necessarily put the writing issues down to lack of challenge or whatever, but perhaps instead to lack of familiarity with writing assignments per se. After all, writing is a subject that extends beautifully, commensurate to ability. I would say that she may need more time and that some of this is becoming familiar with the school's expectations, regardless of actual writing ability.
FWIW, writing a full page in first seems like a high expectation to me.
