Wisp is one of the only "True Supports" in the game who focus almost entirely on assisting another hero. He is pretty rewarding to play because of his global options, despite being fairly weak individually as a result. Make sure to max out his spirits because the damage they do is fantastic(500 damage in an aoe is impressive for the little ball of stuff), and make sure to use hp gain items like Urn, Wand, and Mek to heal up the people you are tethered to!
Here is the much awaited Wisp gameplay! I had a lot of trouble focusing in the start of the game so I missed plenty of last hits and speaking but made up for it with the rest of the match. Wisp is one of my favorite heroes(I like playing full support roles). I hope you enjoy the video!