I've got nothing against mechanics that add challenge into those kind of tactics, it's just that slam is so overused and such a lazy design to do it. I mean one of their biggest issues is that they keep making a bunch of totally static bosses, take the Menagerie for example, the most mobile boss is the Ogre... who walks forward... that's it, that's all it does. The other two in there literally just stand/float still. Slam is a lazy answer to lazy boss design (possibly due to a poor game engine?). I said in a couple of other comments, they need to check out the likes of Dauntless, Monster Hunters etc and get some ideas. They actually had a couple of interesting mechanics in Forsaken like The Machinist missile strikes (again static boss, but it made sense at least)