Currently, in late game, the marines really have two high-tech choices in how they spend their resources, Heavy Armor or Jetpacks. Instead of passive equipment, a high tech weapon could be quite useful.
Quite simply, this weapon would be upgraded at the Prototype Lab, and dropped within its range for a cost of 20 resources. It would be a slow firing, powerful rifle.
5 / 25 is Clip Max Size 135 + 15 per Weapon Upgrade 0.60 shots/sec
Compared to a shotgun; 8 / 40 is Clip Max Size 170 + 17 per Weapon Upgrade 0.77 shots/sec
This is significantly weaker than a shotgun, but has its positive side. It is 100% Accurate - Will always hit exactly where you aim. The down side to this is its slow firing rate. Without support, it will be quite useless, especially against smaller lifeforms.
Its purpose is primarily to kill higher lifeforms from a range. Weakening them significantly before they even get into attack range. Finishing them as they escape.
With support from Shotguns and HMG's, Marines will easily be able to push a hive, quickly taking down fades/lerks/onos.
Key points; - Will not instantly kill a Lerk with Weapons Level 3. Lerk will have 5hp after one shot. - DPS of Rifle to buildings is the lowest in the game, at 108dps. (HMG/LMG/Pistol = 130dps, GL = 270dps, Shotgun 340dps).