We have the lockbreaker module, and it doesn't seem to stop focus fire. Here I propose a different solution:
Target vulnerability scanner: Low slot module
It scans all ships you have locked for weak points in defenses and would randomly activate on one of the locked targets. (or fail to apply to any target) Applying damage to the target during an active cycle would have the following effects with probability depending on damage divided by base hp of ship:
1. Boosted damage
2. Disable the effects of high slot modules for some time (say 10~20 seconds)
3. Randomly cause high slot module damage
Probability of module activating is modified by numbers of target you lock. Assuming locking one target uses Base_Rate, multiple targets uses Base_rate*(1/target_count)^1/2 so the more targets you lock, the higher total chance of getting an active cycle. For example 2 targets give you 0.7*base_rate per target. Two targets gives base*(0.7+0.7) total probability for getting an activation.
(all numbers can be tweaked to improve balance and game effect, lock numbers may also boost raw effect if activation chance is not enough for scaling)
An combat pilot with this module fitted, will in, addition to shooting primary, lock and shoot targets of opportunity and lower incoming dps. It also reduces effectiveness of alpha-fleet type concepts, since it can suppress incoming alpha with well planned spread fire, while dps fleets gets a further dps bonus when trying to out dps logi.
This module also boosts "solo/small gang pvp" since larger groups suffer from the effects of this module more due to the way more locks = more likely to activate.