https://www.reddit.com/r/stobuilds/c..pace_dps_meta/
What is the best Faction for DPS?
Going into ViL, Romulan Tacticals are still statistically the best. However, Federation Tacticals have had a nice comeback, with the Vengeance being a beast with high end cannon setups.
But most importantly, if the Jem'Hadar Vanguard trait is comparable to the ground version (+5% Dmg for Weapons / 3% CrtH / 5% CrtD), then the Vanguard will be the new DPS Faction. This is a big if though, as Cryptic has not given us the numbers of the space trait. They're making us wait for ViL to go live so we can find out ourselves.
What is the best Class for DPS?
As for classes, this game is still heavily biased towards Tactical. Science has gotten better over the years (and is very good in Exotic boats), but Engineers have largely been left behind. Myself and a few others often consider Engineers the 'noob-trap' class now. Engineers are great for new players who have no idea what they're doing, but they're extremely bad when you get to endgame and want to start doing any high level competitive content.

Is FAW still the meta?
FAW = Fire at Will
No. FAW was nerfed a bit with the S13 patch in the first half of 2017. On top of the nerfs, it was then given the worst duration extension trait we've seen via the Tactical MW Cruiser. This trait can give FAW up to 15/20s uptime, but it requires you to be shot once every second.
What is the energy weapon meta?
CSV = Cannon Scatter Volley
CRF = Cannon Rapid Fire
Cannons. Both CSV and CRF have gained buffs over the last 2 years that have made them extremely potent. They were nearly competitive with FAW before the FAW nerf, so the post-S13 meta gave them the opportunity they needed to fully take over.
What makes CSV so good is:
'Withering Barrage' Starship trait off the T6 Defiant / T'varo / Kor
Extends duration of CSV by 4s, giving you 14/15s uptime.
Was recently buffed to have a 90' Firing arc.
What makes CRF so good is:
'Go for the Kill' Starship trait off the T6 Jem'hadar Strike and Recon Ships
Once per 5s, a crit will extend duration by 3s.
Basically means 100% uptime on CRF.
'Preferential Targeting' Starship Trait from the T6 NX
When you use FAW or CSV, CRF & BO will get a +100% Cat 1 Dmg Buff for 30s
Using FAW alongside CRF will allow this to have 100% uptime.
'Directed Energy Flux' Starship Trait from the T6 Husnock Warship
When you hit Directed Energy Mod. or any Temp Ops Boff ability, CRF / BO get a 25% Cat 2 Dmg buff for 15s
Only worth using on ships with a Temp Ops Boff seat.
CRF is only worth using if you have at least Go For the Kill. If you don't have GftK, then you should stick with CSV.
Big issue with CRF though is that with single target focus, so you will have some issues in lower difficulty content, such as ISA. You'll often kill stuff like transformers while the gens are all still up. Also makes it hard for you to help with sphere cleanup, due to often lacking AoE DPS or most likely DPS at all from your team.
With that in mind, just know that CRF is crazy fun, and most of the hate out there for it is due to it ruining ISA DPS runs because it's simply too powerful for advanced content. Is perfectly balanced vs other options in Elite.

Is the Iconian set still the meta? Or is there something better?
The Iconian set still works, but there are better options.
Currently, the most popular option is the Fleet Colony Deflector (the one that gives a buff CrtH/ ShPen, should be 4th on the vendor list), which gives a scaling CrtH/D buff with your current HP. Up to 4% CrtH and 15% CrtD when you're at 100% HP. Can also be Re-Engineered to have mods that work better for your build.
Engine wise, the Competitive Rep engines are very good due to having a built in mini-evasive that triggers when you hit certain abilities. There's versions here that trigger off of drain/ control, weapon enhancements (like FAW/CSV/etc), and heals. I'd recommend going for the heals version, as that will give you more control of when it's active.
Core wise, do whatever you want really. Fleet Spire one works well still, Terran rep one can do ok if you're constantly in combat for a few minutes (takes 1m to build up), and the Competitive one is popular for the 3pc with the Engine/ Shield, which gives you some bonus Resistance.
Shield wise, Iconian still works, but the Competitive with the 3pc ECS is popular. Either the CrtH or MaxHP variants of the shield will work.

Antiproton is still the best damage type, right? No!!!!
Disruptors started to take over way back in early 2016. Nowadays, Phasers and Disruptors are the best choices due to various sets and consoles that buff them up.
Weapon procs were 'fixed' with S13, meaning they barely proc anymore. So what matters for a dmg type now is how many things out there will stack up to buff it.
This change to weapon procs has made Sensor-Linked Phsers/ Disruptors quite popular. These weapons replace their proc with a +5 stat buff to your CrtD and Defense Skills. (2% CrtD and .75 Defense per SL weapon).
The Terran Rep Set Disruptor DHC/ Beam is still best in slot on most builds. It's unique ability is a scaling damage buff that scales as your target's HP lowers. Almost every energy weapon build should be running this. In tests I've done, it's so powerful that it can even be worth slotting on builds where no tac consoles are buffing it. (Tested it with a full phaser setup on the NX, was only 500 DPS behind the Prolonged Phaser....)

Is CrtD still the best mod?
It depends now.
Dmg was buffed up a few years ago, and became a final damage multiplier.
It's generally recommended that Tacticals go for Dmg, and Eng/Sci go for CrtD.
What makes Dmg so good for tacs is that it goes after every last damage buff they have. It even buffs off other [Dmg] mods. A normal [Dmg] mod is a 3% final dmg buff, and the Epic level [xx/Dm] mod is 6% final. A weapon with [Dmg]x4 [CritD/Dm] would be ideal for a Tac, and would give 20 CrtD and a 19.3% Final Damage Buff (1.03x1.03x1.03x1.03x1.06). That's 19.3% multiplied after every other buff on your build...
[Pen] still works ok, it's just that with all the sources of Debuff out there (especially if you have the Cold Hearted starship trait off the 2017-18 Winter event ship), it's not as much of a must as it once was.
Now, some Tacs still run CrtD. The difference is basically that CrtD will sometimes get lucky with RNG and give a slightly higher number. I prefer Dmg as it may have a slightly lower peak, but it will allow for me to have a consistently higher result.

How do I reduce cooldowns?
Aux2Bat has returned to the meta post-S13.
This very old method simply requires 3 Technician Doffs that reduce CDs with Auxiliary to Battery, and 2 copies of Aux2Bat.
If you spec into enough readiness and have a console/ boff for Eng Readiness, it's possible to run a single copy of Aux2Bat.
If you have the 17-18 Winter event ship, you will want to run Aux2Bat to take advantage of it. The massive debuff applied by that trait, and the CDR Aux2Bat allows for has made this the meta CDR option.

Are Leech/ Supremacy still good?
S13 brought in some changes to how power levels affected Weapons. This combined with [Amp] having been changed to not stack on itself a ton, instead being +3.3% Cat 1 All Dmg per stack, has made power levels less important.
However, leech/ supremacy are not as bad as some have made them out to be. Both are still valuable if you're not running a high end build. But I wouldn't go out and spend the 300m+ that Supremacy currently cost.
If you're on an Aux2Bat build, going without either is fine. But if you're not going with A2B, then having at least the leech on is not a bad idea.