I suggest three buffs to Thermal Lance, so it isn't fated to be absolutely terrible outside of construct builds forever. These buffs aim to turn the Thermal Lance into a Thermal LANCE that is truly strong and fun when used well, instead of it being a disappointing poking stick:
1. Reduce vulnerability application speed slightly, but increase base damage slightly too.
2. Increase knockback based on damage(as it is currently) but also proximity to the base of the beam. Reduce knockback slightly to make up for it. The proximity scaling should be strong enough to make it so nothing in front of you will crash into you while you're firing.
3. Scale thermal lance damage and vulnerability application with player speed, adding more the faster the player goes, and reducing it to current values when not moving. So it'd apply huge vulnerability very quickly while dealing huge damage, if you're moving at ludicrous speeds, allowing you to run through the likes of Juggernauts without fear.