Good post TK3600. Agreed on just about everything.
After doing some extensive testing against in a Fury with the front Energy as an HBL, I've come to the conclusion that base stat tweaks are all it really needs.
My initial experiment was making the "maxed out" HBL the base HBL so I gave it stats of:
900 damage/sec (equivalent of bonuses of IPDAI+PD Skill) - ideally this would be scripted "+100% damage to missiles/fighters" and leave the base at 450
Recharge of every 1.33 seconds (50% more than current, i.e. what you normally get with S-modded E Mags)
Increased rotation speed to 75
All other stats the stayed the same (same base charges of 6, 600 range, etc.)
Strangely, this didn't initially feel too strong, despite the insane numbers on the face of it. But what happens when we start throwing a bunch of modifiers on top? Well, about what you would expect with a very unexpected surprise at the end. With IPDAI, Elite PD, S-modded E Mags, and even S-moded Advanced Turret Gyros it was ridiculously powerful swatting down entire waves of Piranha bombs (like 3-4 per burst), could kill Broadswords with 2 bursts, and sustained itself pretty well because its recharge was now to a little under a second. I went with a 2nd HBL on the Fury just to see the dervish of death and it was almost laughable how OP they were...
...until I got to the Carriers themselves. I forgot that Burst Lasers have scripting so that they don't waste charges against ships unless they're topped off. Suddenly, their effectiveness took a nose dive because they do everything in their power to avoid shooting at actual warships if there are missiles/fighters in the area. Even with that wrinkle, they were clearly over-tuned if there weren't fighters around. The sheer damage output was insane and even accounting for the idealized scripted damage, the damage/flux efficiency was likewise insane.
Time to try something new: how can I increase the DPS without increasing the actual damage/sec of the beam? How about we increase the burst size of the beam? Currently it's .3 seconds, let's just nudge it up to .35. Still at 450 damage/sec, but the 15% extra time on target made a world of difference (it clearly reached a breakpoint). It was killing most missiles in one shot reliably. Adding all the extra hullmods and PD modifiers, it wasn't a terror to warships because the extra damage only applied to the PD portion. I kept the recharge at .75 ammo/sec. I think it having 50% better sustained damage vs the Small counterpart is fair. I also kept the turn speed at 75 because I don't know what rationale there is for it being half as fast (or worse) than all other Energy PD.
Final stats that felt good without being obviously OP:
450 beam damage/sec (unchanged. Flux/sec also unchanged)
0.35 burst length (from .3)
.75 ammo regen/sec (from .5)
75 turn speed (from 40)
The significant difference between the above stats and current are the sustained damage numbers. It's 141 vs 82 (~70% increase). With S-modded E Mags, it jumps to 211, putting it pretty close to a Phase Lance. All this with the caveat that this gun really doesn't want to shoot at warships and costs a story point (so I still don't think it's all that crazy). It is a pretty decent PD platform though, especially once you start adding PD enhancing hullmods and skills. It also distinguishes itself from the Small version in the best ways: 50% faster reload, longer/heavier burst damage, greater range, and over twice the sustained damage, though at slightly worse efficiency. It sort of doubles as a mediocre generalist weapon if you invest in it and there aren't a bunch of fighters/missiles around.
I'd still rate it below a Flak Cannon, in general, but with some investment, it reaches parity. For Energy PD, that's pretty good. Is it worth the opportunity cost? Probably not for quite a few ships but for those that can spare it, it makes the HBL about as attractive as throwing in a Graviton or IRAL.