I love the new Polarizer so much that I use it for PD on every single ship with small energy slots. I put it on Shadowyards ships, DME ships, vanilla ships, Diable ships, basically everything that can mount it. I love it mainly because it's an AoE PD weapon in a small energy slot, but also because it role-compresses EMP assault and PD capabilities. And that is also why I think it's still very overpowered post-nerf. No other weapon in the game does either of these, and the Polarizer does both.
One of low-tech's major strengths is their powerful AoE PD weapons. The medium ballistic Flak and Dual Flak are some of the most powerful PD weapons in the vanilla game, second only to the Devastator, and remain among the best PD weaponry even in a heavily modded game. They tear through missiles and lightly protected fighters alike, offering low-tech ships a way to combat missile and fighter spam. High-tech PD is, in contrast, more easily overwhelmed by numbers but better able to remove relatively hard targets. Burst PD's titular burst punches through armor surprisingly well, being able to quickly defeat fighter-grade and even frigate-grade(!) armor, as well as being able to easily remove high-HP missiles such as Reapers.
As a thought experiment, imagine switching the characteristics of high-tech(energy) and low-tech(ballistic) PD. Low-tech would become very vulnerable to being worn down by missile and fighter spam, as they cannot depend on their low-efficiency low-angle shields and armor does not regenerate. An Onslaught that isn't wrapped in Dual Flak is just bait for Claws, Daggers, Harpoons and Reapers. High-tech, on the other hand, would have a dual-layered defense; not only are their wide-angle high-efficiency shields able to absorb lots of HE missiles from many angles, they would boast the ability to shoot down waves of missiles before they ever touch the shields. High-tech flux stats can also more easily accommodate the increased constant flux generation of Flak-style PD, and would not suffer from the soft-flux locking that can occur when heavily pressuring low-tech PD. Fighters that used to be able to pressure high-tech ships through numbers and PD-distractions, like the Broadsword or Talon, are easily shot down by Flak-style PD and thus no longer threaten high-tech ships.
The latter half of this thought experiment is what I have found the Polarizer to do. It takes one of low-tech's important strengths, and allows high-tech to use it to cover one of high-tech's important weaknesses. The concept itself is not unsalvageably unbalanced, but the Polarizer's numbers would have to be poor in order to cover for that very powerful conceptual strength. The Polarizer's numbers are not poor; in fact, they're exceedingly high for a small energy PD weapon. On top of that, the Polarizer also functions very well as an EMP assault weapon.
The Polarizer fires 80 times a minute, and deals 50 Energy and 400 EMP. This is a total of 533.33 EMP DPS and 66.66 Energy DPS. IIRC the amount of EMP damage you need to neuter a missile is the same as it's HP, so a Polarizer is slightly better than a Vulcan for single-target missile removal. Let me repeat that: the Polarizer, a small energy weapon, is slightly better than the Vulcan, the gold standard for small ballistic PD, for single target missile removal. The Polarizer also has significantly more range than the Vulcan, as well as dealing AoE damage.
The Dual Flak deals 450 Frag DPS at 150 damage a shot, dealing full damage within a 15 radius AoE and reduced damage out to a 30 range AoE. The Polarizer deals 533 EMP DPS at 400 damage a shot and has a 25 AoE radius, dealing full damage with 18 radius. That's almost the same. The Polarizer also has 100 more range than the Dual Flak. The Polarizer is about as powerful a PD weapon as the Dual Flak, perhaps more powerful; the Dual Flak is a medium ballistic weapon that costs 12 OP and uses 152 flux/second, the Polarizer is a small energy weapon that costs 6 OP and uses 90 flux/second.
The single downside is that the Polarizer is prone to overkill. It will keep firing at a missile that is EMP'd out until the missile is destroyed by the energy damage. The weapon's AoE and large per-shot damage makes this less of a downside than you'd think; unless missiles are incoming from multiple angles at the same time, a single Polarizer will generally be able to get them all thanks to the AoE.
For comparison, the vanilla standard for small energy PD is around 75 single-target DPS with varying levels of flux efficiency; PD lasers deal 75 DPS, LRPD deals 50 DPS but has much better range, Burst PD deals 214 burst DPS but 64 sustained DPS in chunks of 128 per-shot damage. This very low DPS compared to ballistic PD is because high-tech shields are so much more efficient than low-tech shields; high-tech doesn't need to stop nearly as many missiles with PD because the shields can easily take the hit.
Dealing with fighters, however, is where the Polarizer really begins to shine. Being a mostly EMP weapon, it does not quickly destroy fighters. It does flame out their engines and send them spinning, rendered completely harmless. A flamed out fighter is effectively dead; either it'll be destroyed by shots it can no longer dodge, or it'll just be completely useless until its engines get fixed. Most importantly, EMP damage does not care about armor or hull, only shields. All unshielded fighters, be they as bulky as a Warthog or as fragile as a Talon, are equally vulnerable to the Polarizer. Extremely bulky fighters can be EMP'd out for very long periods of time while the Polarizer works away at their hull; they're dead as soon as the first shot hits, but the refit time is effectively extended by as long as it takes the Polarizer's pitiful 50 DPS to actually destroy them.
On top of being an extremely good PD weapon, the Polarizer has enough range and EMP DPS to function as an EMP assault weapon. 533 DPS isn't the Ion Cannon's 800, but it's still quite good, and given that you can replace all your PD with it you're likely to have more Polarizers than you would Ion Cannons. The choice between 1 Ion Cannon + 1 Burst PD or 2 Polarizers isn't really that much of a choice.
What all this means in practice is that Polarizers go in every small energy turret on every ship. The stock pulse laser Wolf has 2 PD lasers and 1 Ion Cannon in the smalls, all those get replaced with Polarizers. Medusas and Auroras get wrapped in 5 Polarizers, one in every small turret. You can replace every single PD weapon and Ion Cannon on every single variant with a Polarizer and it'll immediately preform better. Why wouldn't you put them on everything? Try wrapping a Vardr in Polarizers. Between the shield and the dozen Dual Flak's worth of PD, missiles and fighters might as well not exist.
If the Polarizer is to remain as a PD weapon, it needs to lose most of its damage, range, or AoE. If it keeps the damage and the range, it can't have appreciable AoE because then it's a Dual Flak in a small slot. If it keeps the range and the AoE, it has to have anti-missile DPS closer to vanilla energy PD; so maybe 25 energy and 75 EMP per shot. If it keeps the AoE and the damage, it has to go down to about 250 range so it can't be used as an assault weapon outside of SO ships. Or, it could lose the PD aspect by default and require IPDAI to shoot at missiles; it'd still very much be worth using.