I think if she has to sacrifice her health, she should be more threatening, like an assassin. Someone mentioned before that backstab is a good choice.
ECHO LOCATION (Default R ability) is for gathering intelligence. Wouldn't it be better if it could also detect traps? If her role is to gather intelligence, then her health should not be reduced.
KNITTING BAG (left click) the picking time is too long. They can hear you picking locks. And if you interrupt, you must pick locks again. Yarn ball (right click) is the most useful skill and FAN OF NEEDLES (level 5 ability) also good.
I am level 20 on MJ and a genre of ASCENDING NEEDLES(level 10 ability).It seems a bit weak in comparison.I mainly use it for parkour, stealing over the fence or walking on the wall because it only exists for about 3 seconds, it is difficult to use. If you fail, you have to start over again. It has no other use. It's a bit of a waste. Get a Yarn ball (right click) instead. I think it could be possible to add the function to disable traps and turrets.
This is just my small suggestion, I hope it helps you
@neon lagoon