1) Cut down on really silly units (Viper Wheels Ripple Rocket Launcher, anyone? ;D)
2) Increase realism (if that would be desirable in such a scenario) by simulating structural/power limitations (You can't mount that Heavy Cannon on a Viper, it hasn't got enough power output and it's too much strain on the chassis from the recoil)
3) Limit the weapons mountable on multi-hardpoint chassis by setting the class mountable on a per-hardpoint basis.
Example;
Weapons can then be organized into classes based on their size, power, and so on.Viper:
Hardpoints - 1
HP#1 Weapon Class - 1
Cobra:
Hardpoints - 1
HP#1 Weapon Class - 1, 2
Python:
Hardpoints - 2
HP#1 (Top/Main) Weapon Class - 2, 3, 4
HP#2 (Front/Aux) Weapon Class - 1
For example, all machineguns are Class 1 weapons - from the humble single MG up to the single Assault Gun. (Dual Assault Gun is kinda chunky, should probably be a 2 or 3)
Cannons vary - HPVs and Lights are Class 1 - Medium is 2 - Heavy is 3. Single assault is 2/3, dual assault is 3/4.
Most artillery weapons are 2-4. Exception; mini-rocket arty and small mortars - class 1.
Laser weapons start at 2 for the most part (but then who uses Flashlights anyway?) and work their way up logically - Pulse; 2, Heavy; 3, Plasma; 4.
--
Then, when you're designing a unit, if WZ could be made to only show the classes that can be fit onto the selected hardpoint, it would reduce clutter and the need to scroll through tons of weapons.
Limiting both the maximum and the minimum classes available will force people to mix and match their army sizes and compositions so that you don't get armies made up of hundreds of cookie-cutter units, even with multi-hardpoints available.
I know it won't happen tomorrow, or the day after that, or maybe not for weeks - but it's still worth considering, isn't it?
--
Starting from here I'm sorting chassis and weapons into categories, starting with chassis;
PROJECT
Viper
Hardpoints: 1
HP#1 Weapon Class Max: 1
Cobra
Hardpoints: 1
HP#1 Weapon Class Max: 2
Python
Hardpoints: 2
HP#1 (Main/Top) Weapon Class Max: 3
HP#2 (Aux/Front) Weapon Class Max: 1
NEW PARADIGM
Bug
Hardpoints: 1
HP#1 Weapon Class Max: 1
Scorpion
Hardpoints: 1
HP#2 Weapon Class Max: 2
Mantis
Hardpoints: 2
HP#2 (Main/Top) Weapon Class Max: 3
HP#2 (Aux/Front) Weapon Class Max: 1
COLLECTIVE
Leopard
Hardpoints: 1
HP#1 Weapon Class Max: 1
Panther
Hardpoints: 1
HP#1 Weapon Class Max: 2
Tiger
Hardpoints: 2
HP#1 (Main/Top) Weapon Class Max: 3
HP#2 (Front/Aux) Weapon Class Max:
NEXUS
Retaliation
Hardpoints: 1
HP#1 Weapon Class Max: 1
Retribution
Hardpoints: 1
HP#1 Weapon Class Max: 2
Vengeance
Hardpoints: 2
HP#1 (Top/Main) Weapon Class Max: 3
HP#2 (Front/Aux) Weapon Class Max: 1
SUPER-HEAVY
Wyvern
Hardpoints: 2
HP#1 Weapon Class Max: 3
HP#2 Weapon Class Max: 1
Dragon
Hardpoints: 2
HP#1 Weapon Class Max: 3
HP#2 Weapon Class Max: 2
--
Starting from here are the weapons;
CLASS 1
Machinegun
Twin Machinegun
Heavy Machinegun
Asssault Gun
Light Cannon
Hypervelocity Cannon
Needle Gun
Minirocket Pod
Minirocket Artillery
Mortar
Incendiary Mortar
Flashlight Laser
CLASS 2
Dual Assault Gun
Medium Cannon
Assault Cannon
Rail Gun
Incendiary Howitzer
Pulse Laser
Angel Rocket Launcher
All Antiaircraft Weapons (Hurricane, Cyclone, Stormbringer, etc.)
CLASS 3
Heavy Cannon
Dual Assault Cannon
Gauss Cannon
Heavy Laser
Plasma Cannon
Howitzer
Groundshaker Howitzer
Hellstorm Howitzer
Ripple Rocket Launcher
Archangel Rocket Launcher