Alright so I think that a 5% damage buff is too small even for PvE. You'll never have a stack of 2 or more unless you use and exotic or are ridiculously close to a boss so that you can melee them. (let's be honest, this is really only useful against them) Not only that, but ignite only last 3 seconds for Sunsingers, so you're basically never going to get that 15% buff unless you're in Radiance and even then it will only be for a short time. A Titan's melting point buffs damage by 50% and last twice as long. My way of fixing it would be to double or triple the percentage and have it proc when and enemy is hit by one of you're abilities and last about 10 seconds maybe, while keeping the stacking ability. At the moment VK is also bugged so that enemies take less damage while burning instead of more. Please fix this.