While Destiny's latest update isn't filled to the brim with fresh content per se, it did do two things very well: it made some significant Quality of Life improvements (infusion and loot drops are much less frustrating than before), and it tweaked almost every weapon class so that at the very least Fusion Rifles are much more competitive in the Crucible. As a further bonus, all of the weapon vendors in the Tower have received a new stock of items to sell, some of which can be quite devastating.
Speaking of Fusion Rifles, there are three new Fusion Rifles that have close to, if not perfect rolls. Putting aside the fact that they all have very good stats to begin with, they also have perks that either increase their stability to borderline unfair levels, perks that increase the range of the weapon (which affect how fast and accurate Fusion Rifle projectiles are), or both.
The Vacancy (Future War Cult) – Thanks to Braced Frame and Rangefinder, The Vacancy comes close to hitting the maximum amount of Range and Stability that you can get on a Fusion Rifle. This means that it is easier to land multiple shots on a target from a longer distance than most other Fusion Rifles, which translates to a weapon that can easily melt people at mid range. The Hot Swap perk is simply a nice bonus for when you get surprised by some charging shotgunner, making it even easier to land shots. The only downside is that the charge rate is atrocious.
The Vortex (Future War Cult) – If you don't like slow charging Fusion Rifles but you like how they are now a decent secondary weapon in Destiny's Crucible, then The Vortex may be for you. It charges faster than The Vacancy, and while it can't reach the range and stability cap as easily as The Vacancy does, it does have very good accuracy boosting perks if you're looking for a weapon that is more suitable for close range. It is much more well rounded than The Vacancy as well, thanks to its selection of perks.
Hitchhiker FR4 (Dead Orbit) – If you don't want to invest time into leveling up with the Future War Cult, then the Hitchhiker FR4 may be your best alternative. It has the same abysmal charge rate as The Vacancy, but it hits just as hard. Unfortunately, it doesn't have the same range and stability boosting perks, but it does have perks that boost aim assist and accuracy, which can lead to some kills that would otherwise be near misses.
Of course, it doesn't matter how good your secondary weapon is if your primary weapon isn't up to par, so you may want to visit pretty much everyone except for Dead Orbit to see if they have something that fits your playstyle.
Not Like the Others (Vanguard) – The undisputed weapon class of choice for Destiny's PvE activities, Scout Rifles hit harder and have better rates of ammo conservation than every other primary weapon in the game. Add in a decent fire rate, Explosive Rounds for cowardly or numerous enemies, and Third Eye so that you will never be caught off guard again, and you will have something that might resemble Not Like the Others. A well-rounded choice for both PvE and the Crucible, especially considering how disorienting Explosive Rounds are in PvP.
The Villainy (Future War Cult) – While it may not be the most optimal kind of Pulse Rifle, The Villainy does have a decent fire rate, high stability, and two damage boosting perks that make it less of a problem when you miss a headshot. Since Pulse Rifles like The Villainy are relatively untouched by the balancing update, it may be worth looking into if you need a decent Crucible weapon.
Antipodal Hindsight (Crucible) – If you can overlook the color scheme, the Antipodal Hindsight has a good mixture of impact, rate of fire, stability, and perks to be one of the more well-rounded Auto-Rifles in the game right now. It may not melt people at close range like the Doctrine of Passing, but it will help you put a consistent amount of bullets on a target at a relatively long range for an Auto-Rifle.
Machine guns and rocket launchers for those situations where everything has to die.
Ruin Wake (Crucible) – As part of the relatively rare super-high impact class of machine guns, the Ruin Wake can easily kill people with just a handful of shots while remaining very stable thanks to Braced Frame. Yes, you will probably have to reload a lot more than you want, but it doesn't matter when you can easily kill another player with what is essentially an automatic Scout Rifle.
Objection IV (New Monarchy) – If you don't like how Ruin Wake sacrifices every other stat for high stability and damage, then the Objection IV might suit your preference for a more well-rounded weapon. It has the same damage as Ruin Wake, but it can have a little bit more range (which translates to slightly more aim assist) in exchange for slightly more vicious recoil.
The Smolder (Crucible) – One of the largest problems with rocket launchers is that if you miss, you're probably not going to have a second chance to kill your target. The Smolder breaks that theory by offering three chances to hit your target, tracking rockets so that you really only have to look in the general direction of what you're trying to kill, and faster rockets in general so that it's easier to hit even the most nimble of Destiny's enemies.