Veteran Melees

Maccabian Mk IV Duelling Sword needs to have Precognition + Uncanny Strike.
It's both extremely deadly and defensive thanks to it's now new parry ability which works the same way as Devil's Claw's family.
Just spam heavies at high priority targets whenever there's an opening, and then just continuously spam parry when you're overwhelmed.
With combination of listed talents and blessings you'll have the easiest time dealing with Monstrosities, just don't forget to tag enemies that WILL die from your parry to regain stamina back from Target Down! , which you can further boost with @Focused_Fire , but in heat of combat you won't be able to get it's max stacks back to then debuff someone with it's full strength, that's why I'm not including it as necessary talent to have.

Catachan Mk III Combat Blade , Achlys Mk VI Power Sword , Munitorum Mk III Sapper Shovel and Munitorum Mk VII Sapper Shovel are pretty much the same oneshot weapons:

Combat Blade needs Precognition + Uncanny Strike 
Power Swords needs Power Cycler + Slaughterer / Supercharge (Depends on breakpoints)
Both Sapper Shovels needs Uncanny Strike + Skullcrusher (Issue with these weapons is not all enemies can be staggered, since it depends on mutators, difficulty level and different buffs that enemies are often apply on each other, like pox gas, and stagger is required for Skullcrusher to work and that's the reason why they're on last place in this tier)


Aridin Mk I Power Falchion , Rashad Mk III Combat Axe and Achlys Mk VIII Combat Axe are strong, but too slow. Trench Fighter Drill is must have.
The Blessings they need are as follows:

Power Falchion needs Decapitator + Energy Leakage
Combat Axes need Decapitator + Headtaker / Shred (Simply depends if you have enough crit or not)


Even though Cadia Mk XIIIg Assault Chainsword and Catachan Mk VII "Devil's Claw" Sword are on the very bottom, that doesn't necessarily means they're bad choices.
Yes, they are unable to deal heavy damage as the rest, but they are still decent enough to not feel awkward in melee, and in general you have to take these two weapons in heavy ranged oriented builds, where you just don't have much talent points to spare on close combat.

While Cadia Mk XIIIg Assault Chainsword can deal significant damage with it's rev special attack to deal with single high priority target in the heat of battle and it feels pretty smooth at handling horde, Catachan Mk VII "Devil's Claw" Sword at the other hand is strong in defensive way, equally strong in comparison with the top weapon in this tierlist, but it's overall low damage lead it down here. Just don't forget to apply Target Down! to get stamina back:

Chainsword requires Shred + Wrath
Devil's Claw... requires whatever feels comfortable in your gameplay. It can be Rampage , Shred , Skullcrusher , or Wrath