I tried to explore the Code Intel source code to find an answer, but looked little bit too complex...

What kind of hinting options Code Intel 2 gives for Javascript? According to source code, it tries to parse JSDoc somehow. Both JSDoc and Google Closure provide annotations which could be made the auto-completion more insightful, less dynamic:

https://developers.google.com/closure/compiler/docs/js-for-compiler

This would e.g. give autocompletion for function arguments which are objects.