I suggest adding a temporary paralysis reflectivity reduction buff to any ship hit by a tazer.
Now, I'm no mathemagician, but here's some example numbers:
1st hit: 100% effect, limited-duration buff (-10% paralysis effectivity) is applied
2nd hit: 90% effect (90% of normal paralysis duration), buff is stacked twice
3rd hit: 81% effect, buff is stacked three times now
4th hit: 72.9% effectivity, the paralysis duration is already cut by almost 30%, buff might stack again if its duration is long enough.
So that using tazers repeatedly will diminish the effect they have on a single target. It basically forces a player to make haste in taking out paralysed enemies, before the resistance buff stacks so high that tazering them any further becomes ineffective.