2. Sunbreaker
Yes, the Sunbreaker is not the same PvP killing machine that it once was when The Taken King first came out. Those were dark times. While the Sunbreaker has been brought back to the pack a little, it still has that balance between offense and utility that made it such a cool class to begin with.
Melting Point is still one of the most useful melee attacks in the game. It greatly increases not only your DPS, but the DPS of your entire team. In PvE, if you need something to go down FAST, Melting Point helps a ton. Fusion Grenades are almost always helpful thanks to how incredibly reliable and easy to use they are. Hammer of Sol is still very destructive in the right hands, and is way more flexible than other high powered supers.
Sunbreakers also get a ton of neat ability modification options that can increase their survivability (Cauterize), speed (Fleetfire), ability recharge (Simmering Flames) and/or damage (Explosive Pyre). The Sunbreaker may not necessarily be the absolute best at anything, but it can still get a lot of different things done, and done well.