I never teach the 8 count basic. Here is why.
1: It is NOT the basic Argentine Tango step. The basic Argentine Tango step is the walk.
2: Good dancers NEVER use it. Why would you teach something that you, personally, would never use?
3: It includes movements that are socially unacceptable. Starting your tango with a leader's back step is like merging onto a highway and immediately putting your car into reverse. In some places this will result in an immediate request to leave the dance floor.
4: Tango is an improvisational dance. An 8 count choreography is the antithesis of improvisation.
5: It doesn't work. A milonga has a unique ebb and flow of movement among the dancers on the floor. The 8 count basic never fits within that ebb and flow.
6: Once a beginner has learned the pattern it takes a long time to get them to let go of it. Why not just avoid the whole problem and not teach it in the first place?