I do not mind them in a general sense. What I do not like is when people insist on doing some that are really not worth the hassle.
The one on Athiss with the Beast of Vodal Kresh where you drag him down to the "lake" so the adds do not come to you is one of those. The adds die quick and it is a pain to drag him down there and sometimes he evades. So not worth it.
Honestly I don't see moving the boss as an exploit. Let's take the Esseles with Ironfist, if you pull him on the higher bridge the adds will correctly spawn but won't join the fight. I personnally see that as clever positioning and I believe that if the devs wanted us to avoid this trick they would have fixed Ironfist a long time ago.