Veteran
18-24% Finesse for 5s on Enemy One-Shot. Stacks 5 times.
7.5-15% Weak Spot Damage. Weakspot Kills also ignore Enemy Hit Mass.
3.5-5% Critical Chance on Weak Spot Hit until your next Critical Hit. Stacks 5 times.
1-4 Burn Stack(s) on Critical Hit to a maximum of 3-12 Stack(s).
You can bring almost any gun and any melee. Melee should be something that allows you to cut through/manage hordes. Melee is your vulnerability.
Optional nodes are "Shock Trooper" and "Deadshot." Deadshot only works if you have Stamina AND consumes .25 per shot. If you're at 0 stamina, you get no buff. Which also means any rapid fire gun will eat your stamina bar almost immediately. Deadshot is basically a tiny burst window for rapid fire guns, assuming you even have stamina to spend in the first place.
Recon lasguns can't take advantage of the "Shock Trooper" enough to really consider it due to a hidden timer in it. The other lasguns will benefit from it though.
There's plenty of nodes on the way down you can swap between. Like "Catch a Break" vs. "Get Back in the Fight"
This build works off the idea you'll be tagging and blasting enemies. Note, your 8 stack tag buff will refresh on any new tagged kill, even if it's a lower stack. Always be tagging your kills and then some.
As for defense, the only thing you need, IMO, is 3 stamina regeneration. Veteran regens way too slowly to pass this up.