The initial aim of most is to be able to go dancing.
Yes, exactly.
I've yet to meet anybody who takes tango lessons for any other ultimate reason – though there's often a qualifier such as "go dancing
as a couple activity with my life partner," "go dancing
to meet people," or "go dancing
because my doctor said it's the sort of light exercise I need." The existence of a qualifier doesn't lessen the desire to be able to dance at the milonga.
At the same time, I have mixed feelings about sequences and patterns. You can embed basic movement concepts and technique in those, giving creative people a framework around which they can improvise. Since not everybody is good at improvisation, they also give less-creative people something to do. That said . . .
The way that lessons
focus on sequences is troublesome, because that sends the message that the dance is the steps. Which, if your aim is to go dancing, is patently untrue. At my weekly práctica, I see four things that need fixing in all the lower-level dancers before they could dance at the milonga, none of which are "not enough steps":
Partner-gazing. Staring into the eyes/at the face of their partner, rather than over their partner's shoulder to see what's going on in their immediate surroundings. I'm sure it relieves anxiety to look at your lover and not some tall, overzealous leader throwing their follower's heels around . . . but until you're looking out for that, you're not ready for the milonga. You'll also develop weird postural issues. All the sequences in the world won't help solve this one.
Foot-gazing. Staring at their and/or their partner's feet. This creates the same blindness as the previous issue. The head is also
heavy, so tipping it downward ruins your axis, making many steps not work as well or at all. And the head takes up space, so tilting it into your partner's space ruins
their axis and means your couple needs more space on the crowded dance floor. Sequences won't help solve this one, either – in fact, they make it worse, because people think their feet have to do exactly the same thing as the teacher's, and grow obsessed with checking for that.
Parking. That is, not advancing down the floor. A good sequence
can help with this, but most of those taught are relatively static, and people aren't shown how to add a forward component to all the elements in order to dance it while advancing. The milonga is not forgiving of those who park. Also, people aren't shown how to curve, pause, or otherwise modify the sequence, so when space gets unexpectedly tight at the milonga, those reliant on the sequence freeze up.
Arm-cranking. The nasty leader habit of making the follower do what's intended using the arms without torso indication or push into the floor. Sequences make this
worse, because the leader has a roadmap of what they want, and if they're not getting that, they don't think "Oh, well" and work with what they do get – they try to force the sequence to happen. The ability to go "Oh, well" and work with reality is
essential at the milonga.
I think it would be helpful to start total beginners out in the abrazo with heads upright and looking over their partner's shoulder. Actually tell them to look over their partner's shoulder, not at their partner or at anybody's feet. Then instruct them to stay moving down the floor even if all they do is walk. Also warn them not to force any movements that don't come naturally, and to roll with what does happen naturally, even if it wasn't intended.
Once they have that working, they can learn sequences and such as "cheat codes" for improvisation. It's putting sequences in right away that's troublesome, because they replace all those other things that are more important if you want to "go dancing" rather than "learn some moves."