How is someone now sharing the gospel with those unaware of it any less an evangelist than John was? According to the linked definition the answer is "not at all." Turns out the Mormons actually have positions called "evangelists." So Romney is not an "evangelical" but holds the title of "evangelist." Make of that what you will.

As far as whether the Great Commission has enduring or extensive weight, I cannot see how any Christian would not be obligated to share the gospel with those ignorant of it. Likewise, an obligation to demonstrate it, and explain it given the opportunity (but not shove it in peoples faces,) remains almost inevitable given how poorly it is generally understood.