Disclaimer: I’m not a game designer in any way, this is entirely speculative.
So a lot of people feel that the Heavy body type is simply not worth the reduced mobility, considering it does not have a great deal more survivability than the other two body types and also the heavy weapons are not that much more powerful than other weapons.
In fact, if you compare their raw stats to that of the medium weapons, you’ll see that apart from the clip sizes and equip/reload speeds, the Chinzor is basically identical to the Euston and the Maximus to the Gerund. This isn’t the full picture though as they obviously behave differently in terms of recoil and spread, as well as having different attachment options. Also, the Hjammerdeim fires 8x16dmg projectiles per burst while the Mossington fires 10x22dmg projectiles (according to Denkirson), with a longer reload time and delay - but shorter time between shots and much better accuracy.
This, however, is a discussion for another thread. What I want to talk about is how the health of the Heavy body type is balanced, specifically with respect to the health buffs available in Brink. Again, according to Denkirson, the base health of Light, Medium and Heavy body types is 120, 140 and 180 respectively. Now, the way that health buffs work in Brink is that irrespective of the source of each extra pip (whether from Hardened, Health Command Post or Medic buff), each extra pip will give you +30, +25, +20, +15, and +10 health. So fully buffed with an upgraded Health Command Post and the improved Medic buff, you get a flat +100 health.
So let’s look at how much health each body type gains from any amount of extra health pips, but also look at how much health they gain as a percentage of their base health:

As you can see, when fully buffed the Light body type gets over 80% extra health while the Heavy gets just over 55%!
What I would propose is instead making the health buffs work multiplicatively, so each pip would give something like +20%, +40%, +55%, +70%, +80% health. Let’s see how that looks:

The light and medium body types are barely changed from the current system while the heavy body type gains a further 44 health when fully buffed, allowing him to survive an extra couple of body shots or a single headshot from most automatic weapons (ignoring kevlar/weapon buffs). This could be enough to make a difference for the heavy without significantly altering the other body types.
Another alternative would be to keep the current system for health buffs but alter the base health of the heavy, for example giving him a base health 240 (60 more than currently):

This would mean that the Heavy always has a significant amount more survivability than the other body types, but would proportionally gain less health from buffs than they do.
Thoughts?