Right now we have degrading sensor range based on weight class, which will be modified on a variant basis per the PTS notes- (adding a small degree of stealth to everyone)
What if we took it a step further? What if we decreased the range at which you could be detected on a per chassis basis?
Locust having -40% detection range, for example.
Atlas (500m sensor range) would detect/lock the locust at 300 meters.
TBR (600m sensor range) would detect/lock locust at 360 meters.
etc.. etc.. (BAP/Sensor module would apply to base sensor range)
This would give lighter mechs (and more pathetic mechs) a bit of a boost.