My Brainscrambler pistols are ranged technology attacks that do Ego damage, so I can use any of the Ego/Paranormal boosting passives or Targeting Computer. I can also use Ego Surge w/ Nimble Mind and Lock and Load. Interesting possibilities.

Yes you can. There was a thread about this. Works nicely too.

It does work, however keep in mind that only a couple powers will be affected by the damage boost of lock 'n load.

I think the ego pistol will somewhat lose their popularity with the new force offensive passive that boosts all ranged physical damage. It will let you use a better item for primary offense stat wise (ego pistols are +34ish dex/rec) and you'll be able to use other munitions power thus taking better advantage of killer instincts. Also you'll be able to pick a model for your pistols at the tailor and not be affected by the lead tempest graphic bug.

Still I will admit that my seraphim/ego gunner is still one of my favorite characters.

Have they fixed the Lead Tempest animation for it? That's a huge bummer for me.

As of yesterday, it is still the all bullets flying in a single direction bugged graphics

Ego pistol usage is still useful for TK melee builds as it only adds to their build to also do good ranged damage (good if you switch to avenger) so those builds don't really lose anything.

Furthermore Lock'n Load with advantage would work really nicely with that build too as you're mostly a melee build so you can easily bring the cooldown to a refresh. I'm not sure if it will still buff the damage of your ego empowered pistols, but the crit chance buff alone is more than worth it for me and don't forget energy reduction as well.

Level 40 green Brainscramblers have +45 Dex/+45 Rec and higher base damage than vanilla pistol powers. Also, all pistol powers except Bullet Beatdown are boosted by Lock and Load.

You are correct that they will be less desirable now that there are legitimate offensive passives that boost munitions attacks; on the other hand, KM and TC don't boost Bullet Beatdown, while Shadow Form, etc., do with the Brainscramblers.

Now that you can build Dex/Ego Shadow Form, combined with the damage debuff the Brainscramblers provide means they are still very, very awesome.

To me, the biggest disadvantage is that none of the power advanttages work with power replacers.