So if I understand this correctly, warp grinders will be given the ability to actually bore through walls! This is the first melee unit that will be able to do so. I had been thinking on how they were going to do siege battles for ogres (since almost all of them are large size) for a while now, and it seems that the warp grinder hints towards the solution in a major way: some ogre units might be able to just smash walls in melee.
This wouldn't be the first time that they test some unit mechanics before releasing it again later: think of deck gunners being released just before jezzails (there are probably more examples but I'm tired so none come to mind).
What do you think? Does the addition of warp grinders open up the possibility of more units being able to melee walls?