NPN base resistor common collector
Yes you can drive it direct in most DC cases, but without a small Series R Emitter followers can become oscillatory with capacitive loads and step pulses.

The value needs to degenerate positive feedback and can be as small as the output impedance, but usually more.  Series R's are often placed between bridge drivers to MOSFET Gates to tradeoff between instability and slew rate.

I don't have a short answer, but I references.
The Rs loop including (Rb/hFE + Re ) must have a Q&lt;1 thus total gain &lt;1 with positive feedback with ESL and ESR of load, otherwise you have an emitter Follower "Hartley Oscillator". When you add a series R, you reduce the Q of parasitic ESL and load Ciss, it is ok to reduce Rb to 0.


http://audioworkshop.org/downloads/AMPLIFIERS_OSCILLATION_BJT_CIRCUITS.pdf


https://www.google.ca/search?q=emitter+follower+oscillation&amp;ie=utf-8&amp;oe=utf-8&amp;gws_rd=cr&amp;ei=Uu4AWIbQEcrcjwT79JLQDA