Hisoka being an excellent nen user shouldn't matter because there are a few good nen users who have died already, and there will be more as the series continues. Shalnark was beaten to death. Why didn't he try and yolo himself back to life? Bringing Hisoka back the way he did opens that door for any high level nen user. It was just a badly executed plot resolution.
The difference is that Shalnark wasn't even in a state of mind to even make a decision such as that.. He literally got blind sided and killed instantly.