> 1. Is it possible to write complex, modern applications (things like browsers, photo editors, etc. — things that would take millions of lines of Java or JS) using this style of programming?
If it were a complex application it wouldn't be very forthy would it? Factor the problem instead of trying to factor a preconceived solution.
> 2. What is “sourceless programming”? Where is a good place to learn more about it?
Sourceless programming was used in Okad a vlsi design tool written by Chuck Moore.