Any software not based on traditional animation principles isn't about animation at all. It may be about programming (like Flash) or Game Design or assembling pre-fabricated movement snippets - but none of that is animation. If you don't know about animation, no software in the world will be able to help you.Toon Boom is clearly based on concepts from traditional animation from the time before computers. For someone like me it becomes frustratingly confusing and opaque as I don't understand the approach.
Now with TB you've picked a very user-unfriendly specimen - I didn't understand it as well when I first used it. I recommend you have a look into TVPaint: that's frame-by-frame with a hands-on approach.
So, how does the software know where that place is you want the line snap to? What's the definition of a shape which can be filled? I assume you know Illustrator: create two overlapping shapes and try to fill just that overlapping part. Doesn't work that way. First you need to tell the program that the overlap is a distinct shape. It's the same with all software. Programmers can only put a certain amount of successful guessing into code.Lines should just snap in place and one should be able to fill any shape with colour
"Vector based drawing" is a contradiction in itself. If you want to be successful in vector based design, you need to get used to constructing complex stuff from lots of simple elements.I am sure vector based drawing tools can be made more intelligent than they are now. As they are, they are clumsy and a nuisance to use for someone who actually can draw. To rapidly draw a simple shape should not require all this tweaking and fiddling which is needed now.
Sorry, if that's your approach to any new tool you might as well give up. You have to learn every day, succeed and fail, before you master any program.It shouldn't be necessary to learn it
Of course you can complain about a bad manual, or a clumsy user interface (well, ever had a look into a big 3D package? Compared to that everything else is simple), or functions which are hidden in an obscure sequence of actions. But never complain about having to learn, because that's the way of things.