I agree. Throwing knives are a more "oh shit I just got a kill" type melee, while say a titan or warlock would be pissed if their melee didn't secure a kill. In destiny 1 I had a PvP strategy. Last word, longbow, and I never even got heavy ammo. I ran gunslinger with knife juggler (gives you back a knife after a precision kill) I would land one or two last word shots then throw a knife directly after the shot. I rarely got ant actual last word kills, only when I didn't have a knife on me. Long range was taken care of with my sniper rifle. Tripmine also helped me secure some kills (2 of em) and gg was icing on the cake. Destiny 2 is a different story. Throwing know knife feels more realistic, yes, like I have to pull it out of a sheath then throw it, but I like it the old way, j mean we are expert fighters and somewhat 'magic' right? I have gotten a few throwing knife kills, but they were mostly due to foetracer and I knew when they were coming out of cover. If I try to prime people with it they do about as much damage shooting me as I do once I get my gun back and ready. Got forbid if I miss... I am usually dead. Better to just shoot, or yea even reload. This brings us to your other point, pve. A handcannon can easily oneshot trash. Why use a throwing knife? Well outlaw throwing knife has a place, like a real ranged melee attack, it explodes. Sharpshooter not so much. Sure, you can have unlimited melee, but there must be low hp enemies, and you must have good aim, why not just use bullets as you have plenty of those. It's fun to kill with them, but not very practical. In pve arcstridera melee comes in more handy, as does nightstalkers bottom tree melee. In PvP arcstridera melee is more consistent and nightstalkers smoke has more uses.

Tbh i have had fun the last couple of days killing titans out of thier smash with my throwing knife...

Throwing knife definitely needs something more than just the fact that it does damage. Other classes get special effects with their melees like blinding enemies, increasing their movement speed, reloading their gun, providing an overshield, regenerating their health. What's throwing knife's effect? That you can use it a little bit further away than a normal melee? So what? Why would I waste time tossing knives at dregs and acolytes when I could just shoot them? This is especially true with Way of the Sharpshooter.