Yes I tend to agree you don't have to be a fluent Spanish speaker to drive here. It will only be really useful if something goes wrong. If you have experience of driving around Europe then you'll be okay here.
If your budget allows then having your own car will give you much more freedom compared to travelling by coach. Coach travel here is pretty comfortable but not as cheap as it used to be and can become very boring over long distances especially during hours of darkness.

My choice would be to fly somewhere like Mendoza or any other starting point, pick up a car, do a circular tour back to where you started to drop off the car then fly back to BA.