FWIW cod, I tend to find that when people complain about lack of communication, it is information about what/how their child is doing. Knowing the overall curriculum is useful, but actually most parents would prefer to know where their child fits into the class in terms of ability and attainment, rather than having this question dismissed as being "irrelevant". Also more information about the range of work in a class and how differentiated work operates throughout the school. Parents get a range of macro and micro messages about what is important in their child's education.
I think that is is also important that communications are read by someone thinking about the parents' perception as well, and also what the most appropriate method of communication would be. This year has been the first time that our dcs have done class tests. Each parent got a slip home in their bookbag giving the %ages attained in English and Maths, together with the class average (the mean). What wasn't explained was which "average" was used, and we had 2 boys who got 99% in each thereby raising the average significantly:- out of 16 boys in the class, 13 came "below" average. Not surprisingly the teacher was inundated by concerned parents (including of course the parents of one of the 99% boys who complained that the tests were clearly not testing enough!).