I actually posted a very similar question a few days back. I'm about to migrate from the Nf6 Scandinavian (a very helpful companion vs 1.e4 during the past 3 years) given that the stronger opposition that I'd like to play these days has booked up annoying responses like 1.e4 d5 2.ed Nf6 3.Bb5+) or the Nf3 bust to my beloved Portuguese.
I was looking for alternative systems with open games + low theory.
Seems like the consensus on that thread was a toss-up between the French and the CK, with the Petrov coming in a close third.
I'm thinking of settling with the CK purely because I don't prefer playing Black with the cramped c8 Bishop to begin with.
Hope this helps!
I think when people say "theory light" in talking about the Caro, they aren't saying that there isn't a lot of theory but that the theory isn't critical.
For example in the yugoslav or marshall knowing the theory is very critical as there is only one set of playable moves and they aren't exactly intuitive. One misstep can wreck you.
But in the caro, beyond the first four or so moves, you can play it pretty passibly by ear. Of course the theory is there, but you can play a good game of chess without it.
My comment was in response to the above.