The replies clarified in my mind what it is that has disturbed me about the series.
Clearly there are some good biographies that people like. From those who commented, Matt Hayday likes the accessible Ricci on Trudeau; for Roderick Benns it is the Beaverbrook and Big Bear bios; L S Fraser likes Big Bear too; and Christopher Moore votes for Saul on Baldwin and Lafontaine.
What made things clear for me was Fraser's comment that the batch of bios of former extraordinary Canadians was being written by a bunch of current Extraordinary Canadians (Joseph Boyden or Douglas Coupland, for example). So we ought to be happy that we are so fortunate in getting such great biographers.
And yet this is the rub. My problem, I now see, isn't necessarily with the series as such, but with the world of contemporary Canadian letters. The choices of biographers are all interesting - get people, mostly fiction writers, who have some interesting connection with the topic. The choices might or might not work.
And here my concern isn't with the editor of the series, it's with academics. Why is it that, for the most part (warning: generalization alert), those who get paid to be experts in a subject (academics) can't and/or won't write genuinely accessible books that people will read?
There are exceptions. The biography of Leacock was written by the historian Margaret Macmillan. Not a Leacock expert of course, but certainly more than capable of the task.
It's nothing against the fiction writers, but where are the academics who want to write to the kind of popular audience that this series will attract? A complex question, with many different kinds of answers. But at least now I know that it was this that bothered me about the series - its context, not necessarily its content.