I don't think anyone will say that DP is a terrible set. I think nearly all will agree that a few minor changes could really make it shine. I have a few I'd like to purpose to you all today.
1. Incendiary Ammunition (Part 1)
Choice is fun, and unfortunately Incendiary Ammunition often feels like it takes the choice from Swap Ammo away. To remain competitive in terms of damage with most other sets, you're forced into using IA, and I'd wager that most will use it over cryo or chem for that specific reason.
What happens when someone gets shot? They bleed. I propose the removal of the added damage effect from Incendiary Ammunition, and instead add it as a "bleed" DoT effect to all of DP's powers.
This will have several effects on the set as a whole. First, adding the bleed effect regardless of ammo type is an easy way to increase DP's damage output, without increasing it's burst potential in PVE/PVP. This will bring it more in line with other blast sets.
Second, removing the damage component from Swap Ammo suddenly frees up a lot of choice in the power. People aren't forced into the mindset of "Damage is King" anymore. But what of the fate of Incendiary Ammunition?
Incendiary Ammunition (Part 2)
What do people do when trapped in burning buildings? Cower in the corner. I propose that instead of a damage component, Incendiary Ammunition should add a short term Mag1 fear effect to shots, with longer animation time powers having a longer fear duration. The stacking of the fear effect, when it eventually overcomes the target's resistance, could cause them to cower until enough stacks fall off that the enemy is able to attack again.
Even if most of the time the target's fear effect ends before or shortly after the next pistol power finishes animating, the time that the target spent cowering was time spent not attacking. This sort of idea runs along the same lines as the rest of the Swap Ammo choices, adding soft control, and making it Mag1 will keep the effect from becoming too powerful. With people no longer being forced to IA to compete in damage, suddenly Swap Ammo becomes possibly the coolest thematic power in the game, allowing you to tailor your ammo choice to situation, or character concept.
The basic premise here is taken from the idea that, if there's an option to cause more damage, most people will take it, even if it's not necessarily fun.
2. Redraw
As a set with mostly longer animation times, DP is affected more by redraw than most weapon sets. I propose the redraw from the set be removed entirely to compensate for its greater than average animations. Pistols are small, they're not two swords, not a battle axe, and certainly not a beam rifle/assault rifle. You can climb a ladder with pistols in your hands, after all. The removal of redraw from this set wouldn't affect characters that use dual weapon sets either, as those sets already have redraw built in. Meaning the pistol character with two weapon sets (TA/DP for example) will still have to deal with redraw regardless.
Now having said all that, this is going under the assumption that redraw is built into weapon sets ONLY. It may be that the game is coded to remove all weapons from the player character as soon as a power from another set is activated. This could have been caused by not considering redraw an issue when the game was originally designed, meaning removing it from dual pistols would require an entire revamp of the way powers work. If that is the case, I won't hold my breath

.
Those changes could really round out the set, as it has great potential, a cool idea, and some of the best looking animations in the game. If you've made it this far, thanks for checking out my ideas. Let me know what you guys think!
Cheers,
Rhio