Ok, so....
1. Putrid Explosion definitely is impacted by Power and not at all by increased Minion Damage. With a Power Build, I had each hitting around 2k with no crit. that's with about 1900+ power. Of course, Toughness mitigates this as when I had them going off against a Guardian, they were hitting for 500. They are also a HUGE pain in the ass to control. They get left behind a lot of the time in Spvp when you go through portals and such, and they'll chase down players that run away across the map without switching to a new target. Not sure if I'm missing some controls somewhere or what, but the pet control was so bad in Spvp, I'm not sure I can use the ability. Also, these things die fast. People AoE or focus them, they're dead almost immediately. There is a 1-2 second delays between blowing up both minions and the blast radius actually seems pretty darn small. On PvE fights, they worked much better. I'll definitely use them in PvE.
2. What I did with the Hps v. Toughness is I simply changed out an Amulet for the same number of each and ran into the Chiefton in the Mists and let him wail on me. With base toughness, I had his Kicks hitting around 4350, his slashes at 2500, and his big burst Dual Strike attack at 4600 per. With 569 toughness amulet, I had kick at 3600, Slash at 1850, and Dual Strike at 2330-3500 per. I'm going to have to dig into this a little more to determine the best routes. The thing that is going to make it easy for me is that there isn't a Toughness amulet option with Power and Condition Damage. Still, without Toughness, you're going to get ass-raped by burst damage, especially thieves and warriors. If it's 1v1, I could usually hold my own and win half the time, maybe. But, if either class gets the jump on you, you won't be able to recover. Just run.
3. Didn't really get to test this as much as I wanted with the server being down the first hour or so. I did run a full power/moderate condition build extensively in Spvp and had mixed results. I'm not sure I like it. I switched back to a High Condition/Moderate Power build and enjoyed that much more and was much more effective. Without a doubt, that's how I'm going at launch. Still, I was trying new builds and utilities. I spent some time with Poison Cloud, which is decent. Takes a bit to cast and is ground targeted, but the cloud lasts 15 secs and continually reapplies the conditions if they stay in the cloud or run back through it. I used that because I was trying a pure Corruption build, complete with the 20% cooldown reduction in the Curses tree. I liked it for the most part, but I don't think the cooldown is needed. Blood is Power is great. And I used Corrupt Boon a lot this time, and that's really a core ability that I'm going to keep I think. It's situational, but ungodly powerful against some players. I came away thinking every Necro in this game should have this ability for pvp. I tinkered with Plague Signet a little bit, and I probably will end up going with that as my third utility along with Power and Boon. I'm not sure it's as necessary to the Necro as Corrupt Boon, but it's pretty close. The assholes this Test were dodging my Deathly Swarm at a record pace somehow, and I had problems when other Necros would Plague Signet my own crap back at me and Deathly Swarm was down. If my heal was also down, I died fast. So, I guess that's what I'm coming away from this Stress Test thinking.... Corrupt Boon, must have. Plague Signet, must have. And for what I like to do with reliance on Death Shroud and Bleeds, Blood is Power is a must have as well.
4. The Chill which gets added to your blind via a curses trait lasts 1 second. That's it. I was very excited about that trait since I use Deathly Swarm so much, but not any more. It's probably very useful for those that want to run Plague as their Elite and chain blind while on a node, but that's probably all. I forgot to test how long the critical effect bleed lasts, so that sucks. Unholy Feast was an instant cast prior, now it has a pretty long cast time which makes it kind of bleh. It's still unreported from last Stress Test, but Ghastly Claws got a massive damage boost to like 1400 or so. I had Axe on auto crit rune, so when I'd switch, i'd always crit with that ability and it would crit each of 8 attacks, probably pulling in 4k damage at least in a full power build. Also, the dagger ability Life Siphon got a massive boost. It hits like 10 times now or something, but it does even more damage than Ghastly Claws, so it might be our biggest individual damage dealer if it hits on all attacks. That's about all I have for this stress test. Oh, and they nerfed the top tier Death Shroud Stability trait in Soul Reaping. It no longer lasts the entire time you're in Death Shroud, now it's just 3 or 5 seconds, forget which one, but ugh.....