Use focus control on your jump and take some time to master it. Many criticize the warlock jump because it's unconventional. Be patient with it and you will find that it is arguably the most versatile jump ability. Sun-singer is incredible for end-game PvE, but seeing as though you already have obsidian mind, I would encourage you to level up your void-walker first. Obsidian mind is among the best warlock exotics when used with its complementary subclass.