Sure it can be, but generally it's not that difficult, especially against walkers, any boss with a big head and sepiks, which are the three main reasons black hammer has got a nerf. If you think that a lot of the bosses in the taken king will be big knights, or ogres with huge crit spots, then you will notice that black hammer might be a problem for bungie, and that's why they have decided to nerf it. It makes the time they have taken to make a hard task worthless, you gotta realise that they don't want you to walk through the tasks that they have set like they are easy, that want you to be challenged, and ultimately to enjoy their game because of it.