So as of today I decided to try a bloodhealing build. It is pretty fun and a total new experience.
When you want to heal with a nightblade the best ultimate is soul siphon. It is a very powerful burst heal and adds healing over time as well.
Now the problem is that when you want to use it in pvp you can't. Because this heal doesn't work on yourself!
This is very frustrating and it would be nice to see it patched with the next update!