Wizards and warlocks are not underpowered.
Warlocks are OP because of eldritch blast with agonizing and push.
Wizards, while the sleep spell is less effective than 5e, the wizard is still extremely strong. If anything I would say that clerics are the most under powered if you choose to heal using actions. Especially when you get closer to the end if EA. Action economy is king.
Goblins in the MM have 7 health, but these goblins to do not. Keep in mind that they have health according to their current level and class. You are fighting intelligent enemies, not hordes of weaklings.
