Is the comma in the Swedish sentence required? Because it isn't in the English sentence.
No, it's entirely optional.
What's wrong with the operation is simple, yet important?
It's arguable either way. I'd accept it (so do report it and see what happens), but I can see a arguments against it, too.
Edit: Four months later, I am now a contributor and have added it. :)
Operation here also in a military sense?
I suppose that would work, yes.
lätt vs enkel?
In the sense of not difficult, they're synonymous.