If I understand well your first two paragraphs, you are saying that rotation (or rests for that matter), if any sense, it has sense when the muscular fatigue appears. So rests are more appropiate in March than in October where there is not muscular fatigue. No?
Well, that makes sense. And I hope at least Rafa does that so that we don't have the Arsenal effect.
Also a point that has mentioned LFC2K7 is important for me. I have less problems with Alonso being rotated because I know Mascherano will be the one to substitute him. Quality for quality, no problem (or not as much problem). It's not the same to rotate Gerrard for Lucas though, the result of that, unlike the first case, is a weaker team.
So I think one of the reasons that indeed has made change Rafa's mind is that in the left we have a consistant player for instance, and in the case of Keane, obviously a good player. When Rafa starts rotating a bit more (due to what Bigmick explains in the last posts) he'll rotate Alonso more happily than Gerrard I think, because the substitution is better.