I disagree, at least for now. The renowned's aren't really worth the bother, so I'd just as soon get past killing them and back to killing a fresh round of spawn for ingredients. As it is now, you loot for a pittance, scout around a bit hoping a reward spawned on the ground, and then twiddle your thumbs for a few minutes waiting for the level 1 spawn to start again. (At least, I do. I always try to clean up the majority of the spawn before going after the renowned at the end, kind of on the theory MAYBE there's a better chance at a reward if you've killed all or most of the spawn instead of getting greedy and doing in the boss as soon as he appears shortly after the last level shows up. At many of the spawn locations, there seems to be a finite amount of spawn so that if you clear one area it stays cleared. Therefore,it makes sense to me to kill all of it off and only then kill the boss.)