You first need to decide what you are looking for...
You are both making a complaint that ELO isn't appropriate for all the games on here like it may be for Chess. There's already lots of threads on how well ELO works (or doesn't work). Carcassonne does have a randomness factor, but all players have to deal with that same randomness and over the long term, it should work itself out. And there's plenty of argument already here about applying something meant for a 2 player game to multi-player games. If you'll look around, it should be easy to find some of these threads.
You're also stating you want how these calculations are made to be put on each of the games here, so that you will know ahead of time you're going to lose 40 points if you come in last place. There are different variations of ELO, but you're essentially proposing that something like:
https://metinmediamath.wordpress.com/20 ... g-example/
OR
http://gobase.org/studying/articles/elo/
or something similar be posted on every invite? (Along with an explanation of the k-rating they use, which they've changed, how they do this for multi-player games, and how the 100 minimum fits in, etc.) There's certainly nothing wrong with having that posted somewhere on the site, but you're proposing these calculations be posted on every game invite? Seems a bit over-kill, and a lot of room to take up. That could also be confusing for turn-based, since it won't end for quite some time and those ELO's will have changed by then.