Guys I need a good Legendary Rocket Launcher to use in PVP... proximity tracking is essential.
Hunger of Crota is terrible for that.
You want something with good base Velocity and Blast Radius. At the top of the pack you have the Iron Banner launcher and the random Crucible drop Ash Factory. The Queen's rocket and the Trials of Osiris one are great alternatives but also randomly dropped.
Close behind, with thee benefit of being sold by vendors, you have The Fear (FWC) and Exodus Plan (DO). Admonisher from New Monarchy has max blast radius but its velocity is so low that Javelin goes from being a nice perk to being a necessary one. Admonisher has potential to be the best of the vendor ones but it'll cost so many motes to get there that it probably isn't worth it. It's got one rocket and low velocity so making the most of it requires a perfect roll.
Next, the perks: ideally you want Tripod and Grenades & Horseshoes (proximity detonation). Tracking is unimportant and way worse. Proximity is by far the most important perk here.
If you get Javelin for added velocity or Verniers and Warheads for a boosted Blast Radius, even better. Don't even look at reload speed or stability. Tripod is less essential on rocket launchers with 2-rocket magazines like The Fear. Stuff like Radegast's Fury and Ash Factory with only 1 rocket in the mag really need Tripod.
If you want a standard, the gold bar of PvP rockets is Truth. It has Tripod, Proximity Detonation, extremely high blast radius and Velocity, and aggressive tracking to boot. Gjallarhorn is also great because it, too, has proximity and good blast/velocity and tracks (also has Wolfpacks that track as well).
If you still don't have a good PvP rocket remember that heavy ammo round in Trials is at a fixed moment. You can swap your exotic between rounds when heavy round is coming and equip Truth or the Horn without losing any time. Once you get a good legendary you can skip this step.