This is a topic that I think has been discussed in the past? At any rate, there is a site I used to visit (
http://www.mbworld.org/forum/home.html ) that has cars arranged in the way you suggest. I no longer visit there as I have 2 different MBs, and, unlike many American cars, there is a lot of information that applies to both models. It is less cumbersome for me to scan down a list of questions looking for clues that may apply to my cars, than it is to scan through multiple sub forums looking for the same question in 2 places, and then scanning the other sub forums if I don't find the answer in 'my' cars pages. In contrast, I often find that reading the responses to a question on models other than mine can sometimes provide the answer I need, and having them roughly grouped together (sedans, sports cars, off road, diesel) makes it more convenient for me.
It is also a lot less work for the volunteer Techs to look in one spot to answer questions than to have to scan 10 or 20 spots and maybe have to answer the same question 3 times.
I think it all comes down to personal preference, but for me this site is more informative and convenient than the other.