Personally I run it all the time on any of my Warlock builds.
I've seen a lot of people, old and new complaining that Destructor is shit but I humbly beg to differ and here are couple of reasons why.
1. Infinite ammo - makes you last longer in the field instead of just shuriken pistol you can fire all the time any time.
2.Ignores shields - perhaps not everyone notices or knows but Destructor is perhaps what makes Warlock one of the best counter unit against shield bros and orcs (and Swooping Hawks ofcourse), but a simple fact that you can take off all of the armour of any melee unit that approaches you no matter if hes running towards you or has shield risen and approaches, he receives direct damage all the time.
This makes up for an amazing utility and once aimed at head it can deal formidable amounts of damage to soften up your target to prepare for the killing blow or perhaps finish it off as you took a leap back when enemy tried to d-bash you.

I highly recommend that spell and toying with it and throwing it into the mix of moves might provide you with better understanding of the spell and as with everything, more practice will make you one zappy wizard.

The spell is great agains unaware targets.
But a little bit tricky against an facing enemy.

But I agree.
Its a good tool I've always equipped.

And do not forget to save some charge for healing

That is, I think, the problem: You need to lose something which helps your whole team in order to be slightly better at killing things yourself. I haven't even unlocked it for this reason. If I'm playing Warlock, I'm doing so to aid my squadmates. If I want to just kill stuff in melee, I'll roll a SS or BS.

It's not bad really. And easily dispatching a stubborn shield bro is helping your team. Unless you have fire dragons around already.

The real question is, worth the whopping 300 LP?

Still not worth the cost In my opinion
downsides:
1. Costs 300lp
2. drains your energy bar for your heals unlike your pistol
3. is a channel skill
4. less range that the shuriken pistol, which is also garbage making it a fusion pistol with shuriken damage
5. takes up a spell slot
6. doesn't go in the pistol slot which means you paid 350lp for a fusion pistol with shuriken pistol damage while keeping the shuriken pistol anyway

Make it 150lp maximum or 200lp in the pistol slot otherwise jinx and protect will get better results for cheaper costs

Actually, a costly replacement pistol would be fair. Still using the same mana pool, but at least you can still have the utility of the other two spells.

1. Infinite ammo only works if you are playing 100% offensive, casting defensive spells for your team will deplete the energy bar enough to limit how much *unlimited power* can you cast at your enemys

2. While I totally agree, shields are only a LSM problem and for only 1 class. 300lp for that advantage is just too much when firedragons and Swooping Hawks can deal fine with them. Heck even going melee vs them has many chances to become a win. Warlocks ARE really good at melee.

Aren't they nerfing psyker force weapons?

I found another power to add to the Destructor List of Uses, because during a match where I used Destructor all the time I found that the enemy (LSM) tend to ignore me and go for actual threats instead, which allowed me to relatively often get behind the enemy and either zap them in the ass or simply just kill them with me Witchblade, though using the Witchbladed seemed to cause aggro and therefore make them attack me

So it seems, I hope they buff/balance spells to compensate that.