1 - Use the NA (North American) rules instead of EU rules, hence Fimirs and Mummies have 2 BP and Gargoyles and Chaos Warriors have 3 BP. Heroquestbyphoenix.yeoldeinn.com has translations of the various packs into NA format with multi-body point monsters (Against the Ogre Horde for example eliminates the 1 and 2 BP Ogres in favor of at least 3 BP).
This is balanced out by allowing more treasure searches and allowing the Heroes to hoard potions between quests.
2 - The Wizard may be weak at first in the NA edition (can't use Borin's Armor, Spirit Blade or Orc's Bane). But he can get the Wizard's staff and cloak. In the Remake he can use the hand axe as well. TO make him more powerful, allow him to draw two random potions between quests.
The quests get much harder on their own after awhile. The Trial is a hard first quest (in NA edition). The final quests are a big challenge and Kellar's Keep, Return of the Witch Lord are much tougher.
If you play Against the Ogre Horde or Wizards of Morcar or Dark Company you will find these very challenging.
Elf and Barbarian Quest pack (especially if playing the solo quests with a default hero without extra equipment) will be the most challenging of all, TOO HARD I would say!
by 
