This was my answer on SO, copy-pasted to here.
In my opinion that list is a mid or high level developer. A senior developer should be able to do all of that plus:
Knowledge of various frameworks and things like Dependency Injection
Ability to mentor and/or train lower level developers
Very strong OOP knowledge with the ability to architect applications from the ground up
Ability to communicate with non-technical "customers" (mangers, marketing, sales, SMEs, clients, etc.)
Of course every job will have a different definition of what a senior developer should know.
With that said, a few ideas on where to find the info you are looking for:
Twitter - Start with following the evangelists, then branch off from there. Lots of great knowledge passes by.
Blogs - Again you can start with evangelists, but I find that you can learn almost anything from blogs. Search Google for a topic, then dig from the links.
For Component Creation, just know the component life cycle in and out, and learn about performance pitfalls with things like Item Renderers and the Display List.
For design patterns (OOP) there is plenty of info, but you can do two things. 1. http://www.as3dp.com/ is a good start. 2. Read about design patterns in Java (Java Head First is a good book). Java and ActionScript are similar from a structural standpoint.
There really isn't a ton of info on Profiling, so just searching Google and reading everything you can is the best you can do before diving in head first.
Probably the most important thing I can say is practice, ask questions, listen and learn. You will alway improve that way.