Best Damage Slotting for Tornado?

My Illusion/Storm can spare only one slot on Tornado to improve damage. What is the best IO for that damage slot?

He already has the Achilles' Heel: Chance to Debuff in Freezing Rain, and I understand that this debuff does not stack with itself.

So that leaves,

Soulbound Allegiance: +Damage

OR

Soulbound Allegiance: Chance for Build Up.

Thoughts?

You only have one slot for Tornado? It sounds as though the rest of your build could be re-worked to get more slots there. We would have to see your entire build.

As a general rule, slotting damage in a damage power is going to provide more damage than a proc . . . unless you are already slotted up for capped damage. The main exception is putting procs in low damage powers like AoE Immobs. Or the purple damage procs hit more often so that they might result in more damage. However, the chance for build up will build up the damage you have, and if you don't have much, then its benefit is limited. Granted, it will also do the "build up" for your other pets, but I would definitely go with the Damage slotting if I had that choice.

Personally, I put that "Chance for Build Up" proc in Phantom Army after they have capped Recharge and Damage.

Well, to be precise, I can spare only one slot for damage on Tornado; the other slot has a +RCHG/+END duo.

Sure, if I had more slots, I'd put more damage on Tornado, and the Build Up proc on the PA. Unfortunately, the build is super tight. Only after the gift of free Fitness is Tornado even possible.

Tornado is kind of an interesting choice for an Ill/Storm. On the one hand, you can view it as an awesome autohit damage power. Against AVs who can't be knocked back, I view Tornado as */Storm's version of -Regen. The damage from Tornado pretty much takes care of the AV's Regen, plus a bit.

On the other hand, Tornado is an extreme chaos/control power. Let it loose in a room full of foes, and they will be flung every-which-way with a chance to be stunned. It is difficult, but not impossible, to use Tornado as a damage power against foes without knockback protection, since you don't have an Immob with -knockback. You have to pretty much trap them in a corner or a cul-de-sac.

Personally, I 6-slotted Tornado to cap damage and Recharge, with some EndRdx. Solo, I use it a lot for the chaos/control. Illusion's damage is single-target, so if a group get thrown around, it doesn't matter much. I don't use it much on teams, except when its nature will be well appreciated. It is really effective on the Control Box in the ITF, for instance -- when the robots activate, a little chaos is helpful.

I can see how some folks may not find Tornado to be all that useful on an Ill/Storm. I happen to really like the power and think it is fun. So I found the slots to slot it up.

With i19, I picked Tornado for my last power for my fire/storm farm toon.... one slotted with a Achilles proc. While I do have Freezing Rain with the same proc (and understand they don't stack), I've decided it was a better choice then Hurricane (after all, this is a farm build).

So far, been using Tornado as a clean-up power once the mobs are down to runners and range loners. Its working pretty good so far (with 3 runs), for even unslotted the damage is enough to kill those I've beaten down with HF/FC.

And against bosses, its just another chance for the proc to fire off.

Ok, my situation is a bit special and I was advise you to see if you could break a few slots free for Tornado but it not... its not the worst choice you can make if used correctly.