The pager detonations were weak enough to be effectively nonlethal unless you're especially vulnerable. That's how you end up with such a low death to injury ratio in the first place.
So per the KPI metric you've chosen, making it more lethal and more dangerous to bystanders would have been better.
Even among the injuries, you're still looking at an awful ratio, since Hezbollah had mostly migrated these devices out of their combatants in favor of newer models, and they were mainly in the hands of civilians.
And all of this is ignoring the blatant international law violation against booby trapping. This was very clearly a war crime.