I was all set to say that Blitz doesn't need a buff as it is essentially the unparalleled offensive tool of all offensive tools.
But then I realized what you were on about.
+420

Trolololó ! (at first glance)

the Blitz have downsides because can make absurd amount of damage if you hit the charged attack

let's see:
1° buff more damage? we can kill trojan with only one well placed charged attack, even in four team party, without any damage increase... think about the Vanaduke changing phase in one charged shot if get buffed more 1000% damage (more powerful than heavy swords? come on)

2° work like sealed sword in each hit = chaos status... only place curse is already overpowered, even shock plus stun or fire plus poison

3° Blitz doesn't work in lockdown because is a multi-hit weapon, like Dark Reprisal series, and players have some frames of invicibility after get hitted, having only PvE utility

4° knockback in each bullet = you lost some damage because of the arc of shoots
and please, Valiance doesn't have any other advantage beyond that and being neutral damage weapon (works everywhere)

5° moving one square back each bullet shooted... 15 bullets in charged attack = 15 squares back... you ll go to another room while moonwalking @_@

6° doing as you wrote, will make the weapon no longer a weapon damage to become a crowd control weapon

if you want to talk about buff or nerf, why don't start with the Fangs of Vog, brandish series, Sudaruska or Iron Slug?

and come on, each weapon has to have its usefulness, if have something powerful, must have a side effect
this is how the weapons in the game should work

blitz charge attack becomes blitz normal attack. Charge attack is changed to *create needle rain over the entire level for a full minute*.

FAIL TROLL IS FAIL TROLL

But pink sound hipster XD

And also I only agree with the moving back part BUT NOT THE INCREASE THE DAMAGE! It's over 1k + dps WHICH IS KINDA OP ALREADY! Ok I think I went a bit over XD

I'd rather see it given penetration than knockback and recoil.

Come on, as explained above, we need weapons with strengths and weaknesses, and each with its own style of use
what you are promoting is just make a strong weapon, which has a weak point of standing on something meaningless to the concept of the game

let this topic go to the graveyard