I figured Tatsu was going to become Katana at some point; bringing her character on and not having that would've sucked, so I'm glad it happened. I actually thought she would've died in the fight with her husband since in the Suicide Squad film Katana will also be in it and we know it seems besides Flash, characters on the film side aren't on the TV side and vice versa. Apparently that's the real reason why Headshot will remain 'off the table' for the time being in Arrow.
However, with her husband dead now, along with their son, it does match up with the comics stories too. Only difference is that in the comics, the sword she uses is a special one and she can communicate with her dead family. The producers have said that they left Tatsu opened up to possibly appear again in season 4. That'd be cool.