An honest question about defense debuffs as secondary effects

Yeah...-defense is usually a 'meh' effect, but it's not 'worthless.' Here are some other cases where it's valuable:

AoE's: these start at lower accuracy, so having some good -defense helps them hit

Long recharge powers: a lot of the most potent powers in the game that need a hit check also have a longer cycling period. A fair bit of -defense goes a ways to ensure they land to do their stuff.

Pets: some pets for controllers and many pets for masterminds are often spawned at lower con than their summoner. If -defense is thrown around, their ability to hit improves.

It also increases the hit chances of enemies to hit each other when they are confused.

Sorcerers and Storm Shamans, Spectral Demon Lords, anything with darkness-type attacks. My /rad defender throws some shots onto them to get things started and suddenly the scrappers can actually take them down.

Against Rikti Drones it's quite useful, since I don't have enough AoE damage output to kill them quickly just with AoE; I land Irradiate and/or Neutron Bomb and that's enough to get the cascade started

On my earth controller it's quite useful to be able to reduce enemy defense before throwing Sands of Mu, since it's her strongest attack and it can't be slotted for accuracy. Recently I rolled up a low-level ninja blade stalker, where it's less crucial but still pretty useful - if there are more enemies present than I can assassinate at once, one of them gets hit with a few defense-debuffing normal attacks before Sands of Mu comes out and it hits quite reliably.

It's true that defense debuff is the least obvious secondary effect in terms of its benefits, but the idea that "it's useless because I obviously hit the first time if it happens" is somewhat misleading. Anyone who's been on the wrong end of a cascading defense failure knows that the attacker doesn't have to be able to hit reliably to get things started.

-Defense as a secondary effect is a lot more useful for Defenders than Blasters... Defender Rad Blast has fast recharging attacks and huge debuff values. Blaster Rad Blast has slower recharge, and only about 60% as much debuff. It's still nice in the rare occasions you need it, but you aren't going to be stacking 60% defense debuff on things and negating Chill of the night or Hurricane on a Rad Blaster.

Powers that reduce defense as a primary effect, like Freezing Rain, Radiation Infection, or Quicksand are a lot more useful since they tend to be autohit and therefore reliable to use on the things you actually need them for. And yes, -defense plus Confuse is a fun mix... I love using Freezing Rain + Seeds of Confusion + Roots (to negate KD) on my Plant / Storm and watching the enemies absolutely shred each other. Of course the -resist in Freezing Rain doesn't hurt either.

Some secondary effects that you can have can allow you to slot an attack less in a relative department ie acc and so more in another, perhaps end. If I was say Broadsword/Invuln then I could get away with slightly less Acc than if I was Claws/SR. Claws/SR might slot more acc but get away with slightly less rechg.

I can't believe I forgot to mention that -Defense helps Vet attacks hit. Not a big deal on a Scrapper or Blaster but a big one on Controllers.

Also, not sure it's been mentioned, but -Defense makes holds more likely to hit with Choking Cloud.

-Defense does help with veteran attacks, but that generally only matters at lower levels. Once you have a decent build and access to epic / patron pools you're not likely to use veteran attacks often. I suppose some Masterminds might keep using them but Controllers get some nice single target attacks in their epic pools that benefit from Containment and can be slotted. Maybe a really low damage Controller like Earth / Empathy or something would.