Dylan doesn't have both single and multiple dispatch. Any method call is going to be using multiple dispatch.
Dispatch is dynamic, except where the compiler has determined (perhaps with hints from the programmer in the form of sealing) that it can be optimized into a static dispatch. One mode of the compiler extends this to help further eliminate runtime dynamic dispatch but that isn't enabled currently (as we aren't sure of the state of that code).
Dylan's OO isn't traditional OO at all in that it isn't like Java, Smalltalk, C++, Python, etc. Instead, it is CLOS-style OO. I wouldn't say that it was new and hot and had to be included as the OO in Dylan is a direct descendent of what was already in Common Lisp and going back from there to Flavors from Symbolics on the Lisp Machine and so on. (In fact, some of the same people were responsible...)
As for #2, I don't really see that at all. Dylan has a very intelligent and hard working compiler that tries to let you have the freedom that you want, but still be able to make things run efficiently. After all, it was targeted originally at hardware from 15-20 years ago.
I'm not a Julia expert, so I won't try to address the other points.
Dispatch is dynamic, except where the compiler has determined (perhaps with hints from the programmer in the form of sealing) that it can be optimized into a static dispatch. One mode of the compiler extends this to help further eliminate runtime dynamic dispatch but that isn't enabled currently (as we aren't sure of the state of that code).
Dylan's OO isn't traditional OO at all in that it isn't like Java, Smalltalk, C++, Python, etc. Instead, it is CLOS-style OO. I wouldn't say that it was new and hot and had to be included as the OO in Dylan is a direct descendent of what was already in Common Lisp and going back from there to Flavors from Symbolics on the Lisp Machine and so on. (In fact, some of the same people were responsible...)
As for #2, I don't really see that at all. Dylan has a very intelligent and hard working compiler that tries to let you have the freedom that you want, but still be able to make things run efficiently. After all, it was targeted originally at hardware from 15-20 years ago.
I'm not a Julia expert, so I won't try to address the other points.