Stat increases
I am not a fan of the stat bet mechanic, as its results are so frequently discouraging.
I suggest the addition of items that will allow individual stats to increase. These would be rare items available in the item spins for Holy Ruins, Barren Land, Thorny Forest, and Ocean Abyss and as occasional rewards for Exploration, Saga Trials, and Wanted Monsters.
For the examples below, I've conceived of the items as newly discovered elements that can be fed to monsters the way EXP Cards are. The value of the bonus given would be unknown to the player until the item is used, and the bonus would vary by probability.
Faunalium (plant)
(60%): +1 to HP; (30%): +2 to HP; (10%): +3 to HP
Galvanium (electric)
(60%): +1 to SPD; (30%): +2 to SPD; (10%): +3 to SPD
Pyromium (fire)
(60%): +1 to ATK; (30%): +2 to AKT; (10%): +3 to ATK
Petronium (stone)
(60%): +1 to DEF; (30%): +2 to DEF; (10%): +3 to DEF
Aquanium (water)
(60%): +1 to MATK; (30%): +2 to MATK; (10%): +3 to MATK
Cryomium (ice)
(60%): +1 to MDEF; (30%): +2 to MDEF; (10%): +3 to MDEF
Cerebellium (psychic)
(60%): +1 to ATK, +1 to MATK, -1 to SPD
(30%): +2 to ATK, +2 to MATK, -2 to SPD
(10%): +3 to ATK, +3 to MATK, -3 to SPD
(Concentrating slows you down.)
Necromium (ghost)
(60%): +1 to MATK, +1 to MDEF, -1 to HP
(30%): +2 to MATK, +2 to MDEF, -2 to HP
(10%): +3 to MATK, +3 to MDEF, -3 to HP
None of these items would be able to increase a stat beyond its stat cap.

I suggest the addition of items that will allow individual stats to increase. These would be rare items available in the item spins for Holy Ruins, Barren Land, Thorny Forest, and Ocean Abyss and as occasional rewards for Exploration, Saga Trials, and Wanted Monsters.
For the examples below, I've conceived of the items as newly discovered elements that can be fed to monsters the way EXP Cards are. The value of the bonus given would be unknown to the player until the item is used, and the bonus would vary by probability.
Faunalium (plant)
(60%): +1 to HP; (30%): +2 to HP; (10%): +3 to HP
Galvanium (electric)
(60%): +1 to SPD; (30%): +2 to SPD; (10%): +3 to SPD
Pyromium (fire)
(60%): +1 to ATK; (30%): +2 to AKT; (10%): +3 to ATK
Petronium (stone)
(60%): +1 to DEF; (30%): +2 to DEF; (10%): +3 to DEF
Aquanium (water)
(60%): +1 to MATK; (30%): +2 to MATK; (10%): +3 to MATK
Cryomium (ice)
(60%): +1 to MDEF; (30%): +2 to MDEF; (10%): +3 to MDEF
Cerebellium (psychic)
(60%): +1 to ATK, +1 to MATK, -1 to SPD
(30%): +2 to ATK, +2 to MATK, -2 to SPD
(10%): +3 to ATK, +3 to MATK, -3 to SPD
(Concentrating slows you down.)
Necromium (ghost)
(60%): +1 to MATK, +1 to MDEF, -1 to HP
(30%): +2 to MATK, +2 to MDEF, -2 to HP
(10%): +3 to MATK, +3 to MDEF, -3 to HP
None of these items would be able to increase a stat beyond its stat cap.
