For most sporting events, time is of the essence. Live coverage of rally isn't really plausible although it's been tried with Super Specials, but it is a lot more fun to watch the recap on the same day it's happened. Watching it afterwards seems like more of a documentary. How many people would watch the Superbowl in mid-February, or Le Mans in July?
I've never watched a season review, but it makes sense that it should be more polished due to the ability to write a good story arc for the season, cherry-pick the best footage from the year and generally polish things up.
I don't have the season reviews, but I do have the old coverage from Speedvision. Every January 1, they used to show the complete season start to finish. I'd go through a lot of videotapes that day.
I think the difference is that the rallies are less spectacular. Of course, there was the Safari. And Loeb has brought a very tidy and precise style to tarmac events - probably one reason he's so hard to catch. All the fast drivers are smooth and look slower than they are.
It would be interesting to compare some stage times - are the current WRC cars faster than Group A? Or even, heaven forbid, Group B? I suspect they are.