Sajungzak,
the extra healing spells are a problem. They don't raise the Wizards BP, instead they raise the generally available BP of the entire group. If he just stays in the background and heals the Barbarian 4 times, then the Barbarian could stay in front of the most dangerous monsters without even have the remote feel of danger. In short term, this is a "cool tactic" but in the long run, it removes the fun from the game.
If you want to give the Wizard wizard-exclusive bonus BP, there should be a spell to heal himself. No target choosing.
Apart from that, i would even say that your wizard is under-powered. It's just the mechanics of healing spells that isn't fitting.
In the end, it is the non-participation that generates frustration. The wait state before the final monster arrives. The "i save myself for the final fight" boringness during parts of the game.
KK addresses this with unlimited fire balls, the EU edition addresses this with weaponry - if you give the wizard player the feeling of active participation, plus a chance to reach the endgame, and a small chance to even survive it, it's perfect. Maybe there should be a find-and-disarm-traps spell, an unlock-door spell (if Morcar builds dungeons with locked doors...

); such things. Practical to use, not too strong if it is one-use.