Jun 24th 2010 9:41PM They're removing ArP altogether and there's an ArP trinket.
May 31st 2010 7:27PM When you're stacked up for P2, drop an Explosive Trap. That thing does amazing damage for 1 GCD. Snakes Traps are good too if you're desperate enough to rely on RNG and don't want to obstruct view of Defile with Frost Trap.
If your raid doesn't need help with the Raging Spirits and you're on the orb, it's possible with Hawk Eye to continue attacking LK through the transition phases (good to keep those buffed up Serpent Stings :D).
Mar 4th 2010 7:47PM You actually lose a lot of ArP pursuing the 4T10 since only 3 of the pieces have ArP. 63 ArP is lost from Logsplitters (although some is gained from the hat) and some crit is gained, but ArP is much more valuable than crit. 258->264 is not a huge loss in stats.
I think this topic is much more complex than has been discussed in this post. E.g. the inability for 4T10 to be modeled (more adds = more procs) vs 2T9 (more adds = more serpent sting crits on them).