Something I have begin to notice in MWO is that builds which can pin-point a lot of weaponry onto a single point for as long as possible than builds which can actually deal more damage but generally spreads the damage across a target.
This is part of why the phenomenon on why players generally only aim for the torsos. All their weapons can easily pin-point to a Left/Right Torso, which also destroys the arms in the process. Thus, there is little emphasis on destroying arms because you can just aim all your weaponry at the torso and destroy a mech or maim it by killing both a torso and arm.
I suggest three mechanic changes to fix this issue by placing more emphasis on arm mounted weaponry while removing some ability for all weapons to target a specific point, thus allowing more weapon fire to spread.
Suggestion One - Multiple Weapon Fire Out of a Single Weapon Port
This is an odd mechanic by PGI. I understand the logic behind allowing multiple weapons to be equipped to allow for more customization but why allow multiple weapons to fire out of the same physical weapon port at the same time?
A good example of this is the Atlas Right Torso 2 Ballistic hardpoint / 1 Physical Weapon port location. If someone equips two UAC/5s in this location, and places both of them on the same weapon group without chain fire, then why does both UAC/5s fire at the same time, having overlapping projectiles? This essentially makes it a UAC/10. This also fools your target because they believe a single UAC/5 is firing but actually it is 2 UAC/5s firing at the same time.
The Cicada is another prime example of this. With multiple Energy hardpoints in the same physical Weapon port, they can fire both laser, which overlaps each other looking like a single laser.
So I suggest adding a mechanic where if multiple weapons are fired at the same time out of a single weapon port, just fire the weapons immediately one after the other. This will help spread a bit of the damage just because of the delta time between each firing while moving and also not be used to fool your target.
Suggestion Two - Arm Actuators Given Meaning
This is a brand new mechanic added, which I believe PGI is planning on adding at some point in time. It is fairly straight forward implementation based on how existing mechs already behave and actually sticks to the TT actuator charts fairly well.
Shoulder actuator - Allow arm weaponry to converge on the Arm crosshair.
Upper Arm actuator - Allow vertical deviation of the Arm crosshair from the Torso crosshair.
Lower Arm actuator - Allow horizontal deviation of the Arm crosshair from the Torso crosshair.
Hand actuator - Allow hand related actions to be performed.
Suggestion Three - Torso Mounted Weaponry Do Not Converge
I personally think this is a big balancing factor to the game and part of the reason why nobody aims on arms and everyone can just place the crosshair on a single location and alpha strike, having all damage hit that single location.
I suggest making all torso mounted weaponry only aim straight ahead, aiming in relation to the cockpit view. Basically, a straight line is drawn down the center of the player's perspective. All torso mounted weaponry fires straight ahead from the mech in relation to this line. As a note, arm mounted weaponry will still only fire straight ahead, like torso weaponry. Just both arms point directly at the Arm crosshair.
A good example is the Atlas. The two Center Torso Laser ports will fire straight ahead, not converging on the location on which it is aimed at, but instead will be aimed at the Torso crosshair, landing in relation to the weapons mounted on the mech. So the two Lasers will land below the Torso crosshair, one directly below (because the cockpit is actually out of the left eye, thus the left Center Torso laser will be directly below you) and the other below and slightly to the right. The Ballistic and Missile hardpoints will be aiming to the below/left and below/right of the Torso crosshair.
What this does is removes the ability to pin-point all weaponry mounted on a mech (unless it is all in the arms) to hit a single location. Thus, placing a larger emphasis on arm mounted weaponry (with intact Shoulder actuators). While alpha strikes will still be around, they will not be the single location devastating that they are now, but instead be the wild firing of multiple systems to place as much damage on the target as fast as possible, not worrying about where on the mech it hits.
And with the greater emphasis on allowing convergence on arms only, players might start choosing to destroy an arm first before taking out the Left/Right Torso, especially on mechs which mount a large amount of weaponry on those arms.
Below is an example of what I am talking about:
Even thought it is not shown above, regarding the arms, you can think of the torso suggestion as the same with arms. Draw a box around each arm, having the boundry around the arms to fit each weapon system attached and the middle of the arm itself.
Then, trace each weapon to hit the same location in a boxed diagram of each arm (as above for the torso, keeping weapons in their own relationship of each arm).
Lastly, then converge that box size to the target based on the distance to the target. Each weapon will land in that box, no matter the distance (but remember, that box grows/shrinks in size with distance) with the same relationship.
This removes all individual weapon convergence, then removes torso weapon convergence specifically, while maintaining the ability to point arms at specific locations.
The large torso convergence square is always centered on the Torso crosshair while both arms (with Shoulder actuators) with the small arm covergence squares will center on the Arm crosshair. The arm convergence squares can be different sizes (different shaped arms and mounted weaponry).
TLDR
Remove ability to fire multiple weapons out of the same weapon port at the same time.
Add arm actuator functionality.
Make torso weaponry not converge, but instead fire straight ahead based on distance to selected target or longest range weapon.
All weapons fire straight ahead.