I know that mass hold and mass charm work differently. The point is is you cant fit mass charm in, you can use mass hold.
Mobs may get more saves on Mass Charm than Mass Suggestion, but MC also has a longer base duration than MS. If your DCs are high enough to be using these spells constantly and consistently in the first place, then they should be high enough to not significantly worry about those extra saves. MC will statistically last longer than MS. Both trump regular Suggestion, unless your goal is to use a single-target charm to gather the mobs (which works excellent BTW
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Correct me if I am wrong...but Symbol of Death is JUST a negative energy DPS not an actual death spell, right? I havent looked at it since the revamp in u9. Thats not really all that attractive with so many other DPS spells available. At least not on a non-PM toon.
PWK: FOD does this job. Since we are assuming heighten, the DC is the same. On a wizzie, the cooldown on FOD is quite manageable and doesnt need another single-target spell to cycle through, especially if you are slotting circle of death and wail already. On a sorc, the cooldown is even less, so the second spell to cycle really doesnt seem like a necessity.
And BTW, I believe I specifically said that Halt Undead was more viable if the sorc was specced for it. It is, however, more common for a sorc to spec damage first (as indicated by the use of earth savant in the same example), and then the more common secondary is enchantment -- so those charms and holds will land. With the removal of blanket immunities in epic, though, necro is seeing a nice upsurge.