Sorry, but no.Luke didn't turn to the dark side but he did exist there for a brief moment to defeat Vader but rescue Anakin.
The Balance that had to be brought to the Force is the acknowledgement that emotions are part of life...The Force included. Not the repression of emotion of the Jedi or the raw emotion of the Sith. Rather thaT our reasoning selves co-exist with our emotional selves.
That's where Yoda and, by extension, Obi Wan were wrong and Luke right.
At the end of ROTJ we see fire purging the entity known as Vader and a PEACEFUL Luke who knows that he had rescued his father and returned him to the light.
I'll be very disappointed if Luke turns Dark Side. It'll invalidate his Original Trilogy journey.