A clone generator is a game engine designed to streamline the creation of a specific type of clone, like RPG Maker. For example, there are a lot of clone generators for RTS and FPS, which give you very little control over your design except for what is relevant to the established conventions of their type of game. Clone generators are not designed to facilitate creative freedom, and it is anywhere from very difficult to impossible to create any type of game feature outside the scope of that engine's clone model. To contrast, a game engine that is not a clone generator is one that makes the most basic necessary features accessible, like a 3D environment ready to have any kind of art and code added into it, and a library specialized for doing things in 3D space, but makes no other assumptions about the nature of the project the user intends to create.
"clone generation architecture AI" by that I am referring to the clone generation features that have been developed into unity over the last few years. They've been systematically replacing their basic features with automated features that take control of your work and pre-process it into some form they assume you want. The last time I worked with Unity, I couldn't even import an animated mesh because the damned AI kept saying it was a humanoid model and therefore has to be assigned some ridiculous humanoid-model-rules that automatically separated it into animation clips with pre-defined physics-based movement and stuff. That was when I knew I had enough and it was time to find a proper game engine. I'm glad I did, because Unity has become a sinking ship since then.