If you're playing peacekeeper you want to do the opposite so that you can gain experience without taking evil points.

If you're playing with the shadowborn specialization, try to outnumber the treasure guardians as much as possible in order to increase the odds of defenders trying to run.You will need to rely on melee units from time to time and choose specializations that cover this weakness. A single Blight Doctor can only debuff a single unit, and massing blight doctors isn't really a feasible way to deal with the situation. Don't expect Goblin Blight Doctors to totally solve the blight immunity problem for you.

Recruiting a theocrat or sorcerer hero early can help quite a lot. Against sites with a lot of monsters or undead you will have to rely mostly on melee units. Choose your battles carefully and don't get overconfident.

The high number of blight resistant/immune monsters can make clearing treasure sites difficult, especially with low HP units.

No racial healing outside of wetlands (see Wetland Foraging).

Only have access to physical and blight damage (mitigated by Goblin Blight Doctor).

Units have low survivability in auto-combat in early game.

Powerful variations of class units, such as Phalanx with Life Steal, Warbreeds with Disgusting Stench(Ability) and Manticore Riders with Inflict Weakened.

Racial Infantry, Pikeman, and Cavalry gain Volunteer at bronze.

Goblin 10% unit discount stacks with Training Regimen.

However, the synergy here goes far deeper than just cheap units. With abilities from both class and race that reduce unit cost and upkeep, no other leader can pump out troops in such sheer volume.

Druid specializations age of wonders 3