One of the reasons paintball is going to fail as an effective "model" for solid gameplay with something like a Mech involved is that in Paintball if a ball breaks on the knuckle of my off hand or the tip of my shoe that I didn't notice hanging out of the bunker, I am out of the game. One of the more effective tactics in Speedball is to throw paint down field and keep the enemy pinned in while your faster team members flank them. Once those flankers have the angle it is all over. It is strategic,but it stops being fun after a bit. (It's also expensive going through half a case of paint and a tank each match)
My friends and I played all sorts of paintball. Every winter we would get our paintball fix by going out in the frozen woods(with heated socks on our tanks and hoppers

) and play.
Sometimes we would play with each player having 3 10-ball-tubes making us have to reload and carefully place shots. It makes up for the instant death as no one can simply spray an area and get a kill you had to actually AIM.
The more interesting variant we played we counted head and torso hits as kill shots. Shots to the arm would require you to hug yourself with it(put your fist on your chest), legs would mean you couldn't flex your knee, both legs and you would be prone, and such. Getting shot in your main arm and having to fire off-handed was really interesting. Losing the mobility of you leg or even both legs meant you could still contribute, but meant you were now limited to trying to hold onto the area you are in.
We also tried a zombie game. Once shot you became a Zombie. You could no longer fire but you could still move at a walk, no running, and a headshot would take you out for 1 minute. If a Zombie tagged you, you were a zombie. This was Free for all and last man standing won style game. We would time the game and see who could last the longest. The area we played in had to be a bit smaller than normal.
So while the "on hit kill" games were interesting we found a great deal more fun... and skill... in some of our other game styles.
Mechwarrior should be a bit slower paced than CS/Quake/Unreal/TeamFortres/BF/CoD.
I still think the game would be better if we went back to normal armor and altered how weapons fired a tiny bit.
Lasers are on/off. While on they deal damage and generate heat at a consistent level equivalent to their TT damage over 10 seconds. So Medium laser does 5 damage and 3 heat over 10 seconds but is continuous and can just be fired constantly. Other weapons deal their TT value of damage and heat divided by how many times they fire per 10 seconds.
so AC/20 fires 2.5 times in 10 seconds. It deals 8 damage and 2.8 heat per shot and gets 2.5 times the normal ammo per ton in the TT. This emulates the damage spreading out from "dice rolls" but leaves those who are skilled enough to constantly hit one location a chance to do so.
PPC would do 4 points of damage on a shot meaning even 6 of them wouldn't core a mech.
Now we set the ranges back to normal, and introduce the heat scale where movement and accuracy get reduced as you gain heat. Since weapons and heatsinks are now in sink for heat generated and dissipated it is fine to have those other things in the scale. High heat alphas will still push you to the point where you are less accurate and that means those second and third shots will have less chance of hitting the same location.