Alright, wisp is amazing, but she could be even better! She has one HUUUGE downside... cosmetically: any bright color will completly blind you when using her sun beam... abd that's it really...
Now for some improvements!
Will-o-wisp: range mods increase the speed of the ghost, making you wait less and giving the ability that little bit of quickness that would elevate it to greatest movement ability ever (not counting nova, that's cheating!)
Breach surge: opening enemies to finishers would make this ability top tier, especially with a dagger
Sol gate: damage is good, feels amazing to use, buuuuut.... come on... it's a beam of pure sun energy... it needs punch trought!
Conclusion: wisp is a great success! With small buffs, she'll be able to enter the meta without much resistance!