what are your concerns with these? Is it that Tempest Strike could be spammed and two hit players, and Lightweight Knife would easily be able to clean up most players with the scorch damage? If so, Tempest Strike's damage against players could be reduced down to 60 per wave, keeping about the same total damage, but splitting it into two segments amongst one melee charge. I did envision this being a little slow, similar to Flechette Storm. Anyway, Lightweight Knife would still have about a 10-12 second cooldown per charge at minimum (don't remember right off), so it wouldn't be back-to-back spamable, even if you're using Gamblers Dodge with Singeing (also I thought Crucible had checkmate modifiers? I haven't played in a while). If it's still a concern though, the cooldown multiplier could be cut down to -200% in PvP

I was thinking about how lightweight knife already has 2 charges, and then gives knife trick no purpose when it comes to scorch with its bonus of radiant and for tempest strike I was thinking about if it gives an extra melee then people would use it just to have another melee and not use the strike. But yes, also the easy spammablity, maybe just keep it a full charge and if that wouldn't help much give it a tad more damage.

for Tempest Strike, you are sacrificing one of the two very powerful Arc aspects that are Flow State and Lethal Current just to gain another melee. There's no reason to have a second Combo Blow, but this would pair nicely with a buffed Disorienting Blow, (though I don't think it would be overpowered or anything). The main purpose is minor enemy clear, though, and sometimes to apply Jolt to tougher targets. I don't really see the point of a damage buff. This Lightweight Knife buff would give it a big utility bump, but I don't think it would overshadow Knife Trick, as it has its own use cases just as the other Knife options do. For example, Proxy is something used for general add clear, Weighted deals the most damage at the cost of an accuracy requirement and a wind up, Knife Trick is a mix between decent major damage and a bit of utility, and Lightweight would have to lowest damage potential with the highest utility cases. Not only are you currently able to chain it without using Ember of Torches, these changes would give it a fast recovery rate if you happen to miss a headshot, and the Scorch stacks from both Knives add up right to the threshold of an Ignition, allowing you to easily create one by simply using any source of Scorch, or Ember of Ashes. Additionally, it would make Fragments that deal with both Scorching and Ignitions more accessible, as you wouldn't be bound to just Knife Trick with Gambler's Dodge