Is the Amethyst spell "Alter Allegiance" to good?

I’m about to run a AHQ-re-reforged campaign and one of my players showed me his Hero (a human -> Wizard - > Adept -> Mage with Amethyst spells) and commented that he is just going to cast “Alter Allegiance” all the time as it was such a great spell compared to everything else. Looking at the spell sheet I am fearful that this spell seems very overpowered in both reforged and original AHQ.
The wordings are:
Original AHQ and Enhanced AHQ
Roll a dice. The Wizard may pick that many enemy models within six squares. Each of the chosen opponents must make an Intelligence test. If the test is failed, the model changes side – it is now controlled by the Wizard player, and may even attack its former comrades. The effect lasts until the end of the next exploration turn, when the model reverts to enemy status and runs away.
Reforged
RANGE: 6
TARGET: A number of figures equal to the caster’s Intelligence
DURATION: Until the next exploration turn.
EFFECT: Targets must make an Intelligence test. If the test is failed, the figure now acts as a Henchman controlled by the caster. When the spell ends, the targets flee and are removed from the board.
RESTRICTIONS: Cannot affect named Enemies or Characters
In both rules it only uses a single spell component.
So considering most monsters have INT values of about 5-7, this hero is going to walk into a room, cast Alter Allegiance and convert 2/3 of the monsters to their side to fight for them. After the combat those converted monsters then instantly die. The hero has an INT of 11 and enhancing so, by reforged rules, can affect 11 monsters each time they cast and they are all at -1 to their INT tests.
To me that sounds super overpowered compared to many other spells.
What’s other people’s thoughts on if this spell is too strong and what are some options to reduce it’s power. Once idea I just had is that the models that “run away” don’t drop their loot so the party might not earn so much?
The wordings are:
Original AHQ and Enhanced AHQ
Roll a dice. The Wizard may pick that many enemy models within six squares. Each of the chosen opponents must make an Intelligence test. If the test is failed, the model changes side – it is now controlled by the Wizard player, and may even attack its former comrades. The effect lasts until the end of the next exploration turn, when the model reverts to enemy status and runs away.
Reforged
RANGE: 6
TARGET: A number of figures equal to the caster’s Intelligence
DURATION: Until the next exploration turn.
EFFECT: Targets must make an Intelligence test. If the test is failed, the figure now acts as a Henchman controlled by the caster. When the spell ends, the targets flee and are removed from the board.
RESTRICTIONS: Cannot affect named Enemies or Characters
In both rules it only uses a single spell component.
So considering most monsters have INT values of about 5-7, this hero is going to walk into a room, cast Alter Allegiance and convert 2/3 of the monsters to their side to fight for them. After the combat those converted monsters then instantly die. The hero has an INT of 11 and enhancing so, by reforged rules, can affect 11 monsters each time they cast and they are all at -1 to their INT tests.
To me that sounds super overpowered compared to many other spells.
What’s other people’s thoughts on if this spell is too strong and what are some options to reduce it’s power. Once idea I just had is that the models that “run away” don’t drop their loot so the party might not earn so much?