I say yes to having really strong HNMs that take skill and effort to kill, want to make it timed? Ok make the time every hour and make the HNM pop ANYWHERE in that particular zone. That's right make the HNM a REAL hunt. The real competition will be finding the NM, getting your group together and then taking him down before another group can do the same. Make the HNM hard enough that someone wouldn't be able to hold the NM for longer then 1min with out dieing to prevent holding. Pulling the HNM to far beyond his claim point would cause rapid health regen to prevent kiting. Just spit balling but honestly if they are going to make HNMs that roam and spawn every hour they should make them spawn anywhere in that zone so that its a real hunt for the HNM and not just 3 groups standing in one spot spamming a macro.