The M20 mine one shots the Luchs. In my opinion it's a must have vehicle for every game, especially on maps with predictable vehicle pathing.
So the game design is broken. Except for basic units (rifle/cons/volk/gren) no other unit should be that mandatory to let you survive in the game vs a dedicated faction.
More than broken if you considere the unit ability "mandatory" so easily counterable.
Next, comparing greyhound and Luch is interesting in fact
greyhound is:
light vehicle
low base dps
canister shot ability with a close range, 40 ammo per shot. dps infantry hard counter
medium speed
Greyhound requires:
A dedicated commander.
40 fuel.
Investing 40 ammo in skirt to be durable.
Luch is:
Medium tank
Dps infantry hard counter
Dps Light vehicles
high speed
Luch requires:
80 fuel for the SPH.
50 fuel
So now, 3 USF CP (remember USF doesn't build building and so CP are going slower) + 40 fuel (+ fuel cost of captain/Lieutenant) or 80 fuel + 50 fuel make both units (based on a balanced match, nobody dominating and USF faction going lieutenant or captain at 5/7min mark) hitting the field pretty much at the same time. Greyhound would be first but his windows of action is really short, a luch alone kills a greyhound alone in a really short time and since luch goes faster, a greyhound has little escape options.
About the killing potential. The statement: greyhound wipe squad in no time is true if you're paying attention but.
Greyhound need to be close to his target, the target need to not be moving. Cover has little effect on the canister dps.
A Greyhound cannot kill a retreating full squad.
If you hit the retreat button at the moment the greyhound shot with his canister, there is a potential squad wipe since your squad members will be closed together in the first step of the retreat.
If your full squad is retreating, the greyhound cannot chase it and use its canister shot and kill all models, unless they have been blocked and regroup in their retreating path.
The Luch has more range, making him more difficult to target by zooks and other AT capabilities. So it shots earlier than the greyhound. It also uses his total dps faster since there is no cooldown for its dps and its dps is already high at max range.
About the squad wipe potential, if we are counting the time to go at range and the delay before the canister shot, a Luch is close to the greyhound in term of time to wipe a full squad. What make the difference is the number of models in the squad and the cover. Luch dps is impacted by cover.
But unlike the greyhound, the Luch can Dps his target and next run after it if it retreat dealing the same amount of dps and so finishing the squad. His dps isn't also costing 40 ammo per shot and has a really short cooldown, not comparable with the Greyhound ability delay.
So are both units dealing too much dps. Yes, both should see their dps reduced to let infantry squad a wiser window to react and if necessary to escape.
Now both units aren't using the same mechanism to deliver this dps and Luch>Greyhound in a 1vs1 encounter
Luch Pro:
overall DPS higher
DPS from farther
High dps on the move
highest speed
can chase running retreating squad
More durable
Kills all type of light vehicle in a duel
for the only cons:
Hit the field a little bit later
cost a bit more fuel than a greyhound
Dps impacted by cover
Time to wipe a bit longer but still in most of situations faster than an average player capability to react vs it.