Hi Alberto,
I interpret your dream as a question: how can I effectively improve my tango, and get out of my "cage"?
What I have found is that I improve - in my technique, in the expanse and usefulness of my vocabularity, in my musicality - specifically through practice. Practice doesn't really happen at milongas - milongas are primarily about socializing and enjoying what you already know well in the dance. Practice happens for me to some degree at practicas, but only with concerted effort (since often at unguided practicas I find it tempting to relax into just dancing as if at a milonga, rather than actually working on improving what's happening). The situations in which I find it most productive to practice and improve is at guided practicas and practicing at home - by myself and working with a dance partner. If you can, find a space at home with a suitable floor (smooth, wood ideally or perhaps tile or concrete) where you can set up a few mirrors to see better what is happening, and convene with a dance partner (or ideally with one of several you periodically work with) to iron out the rough spots and also try things that you've learned in classes but haven't yet mastered. Also use the space to work on drills that you learn from a teacher - walking drills, balance drills, etc. Go to guided practicas, where people are specifically practicing - stopping to talk about how things are working and how they can work better - where drills are taught and done, and where you can get expert help on trouble spots. Seek to work with people at various levels - more skilled than you and less skilled than you - so that you are getting helpful feedback, and also not relying upon the higher skill of your partner to turn an ambiguous lead into something beautiful and musical but instead are obliged to lead clearly, effectively and musically. Most importantly, of course, understand that it is a constant work in progress for all of us, and so when things don't go the way we hoped, the onus is on both partners to adjust what they are doing, to make it easier for the other.
Bear in mind, the notion behind the "50 steps at 20, 20 steps at 50" is that, ultimately, the dance is enjoyable not by virtue of the expanse of one's vocabulary, but rather by how one uses the vocabulary in musical and interesting (perhaps even surprising) ways. Any given movement (a single walking step or weight change, even) can be done in innumerable different ways, incorporating variables of speed, density, physical body position/posture, and so on. This and how movements are interlinked (also having innumberable possibilities) is what makes for compelling and enjoyable dancing, far more so than executing some fancy piernazo.
I hope recounting my personal experience (and aspiration, frankly) helps you in some way.
I do like your idea for playing back video instruction at slow speed, and now want to invoke that for video I have from various workshops I've taken.
Cheers,
Tim
