I can't put Johannas skills in this guide on this site. Im sorry for that. But my Skillbuild is:

lvl 1: 4th skill (Regenmaster)
lvl 4: 4th skill (Regen + activ Hot)
lvl 7: 1st skill (CD Reduction per hit)
lvl 10: 1st Heroic (flying girl)
lvl 13: 3rd Skill (Slow of DOOM)
lvl 16: 2nd Skill (Fanatism)
lvl 20: 3rd Skill (undestructable)

If you want to see this Build ingame, just watch my Video on youtube :) Im sorry to say that, but its in german :D If you just want to see Johanna in action mute my voice and enjoy :D

https://www.youtube.com/watch?v=CpUauCRBoLo