I agree with the point that the Year in Review articles are "space limited" in a sense, but I don't see what's wrong with Toby's solution: let the articles grow until they get too big, then unload the less important stuff to something like [[Books published in 1962]], of course linked to from [[1962]]. The most important books could still stay on [[1962]].
We could now try to come up with some hard and fast rule as to when a list in a year's article is too long and deserves its own page, but we could also just leave that up to judgement calls, like anything else really.
Robert mentions another problem: some fans will add entries to years' pages, thus skewing their "importance". That's true, but it is a problem throughout Wikipedia. Many topics are covered from a certain angle, probably because that's the angle the original author liked and/or understood best. The hope is that other authors will show up over time and add other angles. We should expect the same to happen on the years' pages.
Axel