ECS as you describe it sounds like a good idea, but notice how it is a step away from OO which was supposed to keep code and data in a single encapuslated thing

ECS as you describe it sounds like a good idea, but notice how it is a step away from OO which was supposed to keep code and data in a single encapuslated thing called an "object". Now our componenents are nearly just plain-old-data and entities are slightly more sophisticated data-structures for tying them together. All the code is now kept is "systems", which are starting to look very much like plain-old modules. No doubt the OO language will give you some useful tidbits, so that you can have slightly non-trivial getter setters and whatnot. But the design ends up fundamentally procedural -- which I say is good thing.