It can be done, but its gonna take a lot of work, and its not just a game of numbers. Buff this damage, nerf this damage. There needs to be specialities to predator weapons.
As it stands right now, we have 5 melee weapons for pred. As far as I am concerned, No matter how much they nerf the combistick, it will be better than every other weapon because it can be THROWN.
So what do we do? I think its simple.
Elder sword, wider swings, make it the weapon for hitting multiple enemies at once.
Handheld Plasma caster, Buff damage a bit, so that it can down a fireteam member in 4-5 shots point blank, but slow its fire rate. Its effectively now a melee weapon that cant be parried. But at long range, it should be as piss poor as it is now.
War club, Slow the swings even more. Make it break parries, Slower swings means easier to dodge, Breakable parries and maybe a bit more damage means it will be good at punishing players that sit in a corner of a building.
Smart disc, Full rework. Pred shouldnt have to control it, Make it do its thing and try to return automatically, Leave damage piss poor. And if it hits something on the way back, let it get stuck as it does already.
Combistick, Remove the ability to hit multiple enemies. Its effectively a spear, not a double bladed lightsaber, Make it excel at single target DPS, but it is parryable as it is now, let it be thrown still.
Keep everything else exactly the same.
Boom predator weapons balanced.
As for fireteam weapons, I hate to say it, but those are as simple as damage buffs. Assault rifles and smgs need to be buffed. first two pistols too tbh. Snipers need to have any scopes below a 5x removed, force them to be used at range. Minigun needs tighter spread, GL should get impact grenades back.
(Copied from my comment on another post.)
Edit 1.
Down range perk, up to 5 perk points, make plasma caster charged shot one shot again. This will give the plasma caster power back to scouts and even hunters, but also force berzerkers to gimp themselves to use it
Edit 2
Smart Disc. I have completely changed my opinion on the smart disc over the past 5-6 hours, and I think that flying it is honestly fun. Heres my suggestion though.
Decrease the light trail it has, to make it a little more difficult to tell where it came from. Keep the default flight speed the same, but increase the boost significantly. Default speed for turns, boost for attack.
When a player is using the smart disc, and cloaked, make it so that even very close AI dont attack. Being attacked by random AI spawning on you, and losing control of the disc is frustrating. Even more so when you consider that I am cloaked, and not moving. There is no reason that AI should see me.
And finally, Remove the ability to destroy the smart disc. I have had several games now where I throw it, pop off plasma, and then it disappears. At first I thought it was a bug, but now I am fairly certain that the smart disc, if stuck in a wall, can be destroyed. Remove this please, as having to retrieve a thrown weapon is good enough, you dont need to take it from me like that.