"unlocking" your unconscious mind isn't a difficult task. most successful people have done/do it.
Basically the subconscious mind acts like a script running behind your conscious mind in the background.
the subconscious records and store EVERYTHING, even things your conscious minds slips or doesn't grasp.
to "unlock" your subconscious requires a careful watch on your own thoughts as well as the things you tell yourself.
for example, saying "I'm not good looking enough for a girlfriend" would make your subconscious mind actually make it so women don't find you attractive.
saying "I know I'll bag a bad bytch" will actually make your subconscious mind work to bring this about.
Subconscious mind does not differentiate between "good" and "bad"
once you give it a command to execute, it will do everything possible to bring that about.
Well yes, that's a good point. But that's not true I think, because an unconscious mind is not only tracking current thoughts as you said it holds onto everything. You're not able to access certain things unless you're given stimuli which brings upon a memory, therefore unlocking the unconscious is not just monitoring your thoughts, but this is a good idea although while monitoring your thoughts you must live in the present which can cause a conflict.
Now this technique that you speak of is good for being able to develop yourself into something you are or aren't, but just by monitoring those thoughts you must explain to yourself why you think this way, now you can't do that unless you unlock the unconscious which you can't exactly do by monitoring your present thoughts.
This is my theory in response to yours.