Well with any language you have to teach a little bit of convention to go along with the rules, and the convention on when to use parens in ruby is mostly standardized from the code I see.

But yeah, I'm sure there has to be a better language for learning out there, I just don't personally know it. I originally learned with C++, and I remember the terror that were pointers at first. When I had a class that taught me Scheme, I remember thinking: "hey, I could write this code on paper without even testing it out if I wanted", which was the polar opposite of my C++ experience.