How about making a stat bonus from the heavy skill tree giving you 5% dam resistance per lvl? And personally I wouldn't have an issue making the heavy d-suit skill a 10x skill to help compensate for the buff.

Edit: left out important part

So... I don't think it's a secret that I have been using tanks and dropships a lot this build. I've also spent a fair time running AV, so I was pondering ways to make both sides more fun.

Right now, your typical AV encounter when driving a HAV ends up one of a couple ways :

1. Most commonly, a group of the enemy team will switch to using the totally harmless militia shock starter fit. When seen, the heavy is blapped by the HAV which merrily continues its bloody rampage
2. You get a couple very loosely or uncoordinated people with non militia AV weapons peppering the HAV, forcing you to relocate and recover, no serious threat, probably killing a couple people while you flee.
3. You come across a well coordinated group of prototype AV users. Your tank is probably going to die.
4. The other team has a tank (Or more than one) This generally comes down to the AV units on both sides and how decent at aiming/driving each player in the HAV is. At least one of the tanks is going to die. Circumstances described generally dictate this.

Your typical AV encounter as a AV infantry when facing an HAV

1. You've got nothing but the militia shock starter fit for AV (Maybe tweaked to add AV grenades). Very few people on your team helping you. You die a lot whenever the tank sees you.
2. You've got decent AV fit but your team isn't supporting you. You can make the HAV flee by yourself, but without excellent positioning and/or the HAV driver derping... It's usually going to get away. But if it gets a clear shot at you, you're gonna die a lot.
3. You're with a group of four friends in your squad, and you're all decked out for vehicle murderin'. You pepper the HAV nonstop and can likely kill it. Without using cover/hills to your advantage to avoid splash/direct damage you're probably going to take heavy losses in your squad while killing the tank still, but a flawless destruction without losing anyone in your squad is possible.

Now, this seems like this is how things should be. HAV's have an edge against infantry but are killable. The main problem is, that during game design CCP probably didn't account for the fact a lot of players would be well... stupid. On paper the current stuff all works fine. But in practice, you've got HAV's rolling around relatively unopposed for the main reason that most people simply do not know how to kill them and cannot work as a team to do so. So where does this leave us? If we buff AV weapons, a coordinated squad will just slaughter a HAV without it having a chance. If we nerf HAV's, it's mostly the same thing. In a perfect world, we wouldn't need to change a thing and tanks would be far from 'immortal' as-is.

So, I have a slightly different solution. A massive bulk of my kills as an HAV driver is heavy suits. They are supposed to be able to stand toe to toe with enemy vehicles, but they're nothing more than fodder. I'm proposing a massive resistance buff to the heavy only against vehicle main and secondary turrets. This effectively increases their hitpoints against vehicles without making them impossible for infantry to counter. All the while, it reinforces the heavy suit's role as an anti-vehicle platform while still making them easily killed by infantry without teammates to support them.

I'm thinking the heavy should be able to survive at least one direct railgun blast. Splash damage from missiles and railguns should do practically nothing to a heavy, but enough to add up over prolonged engagements. This change alone would massively change the flow of a game, as a squad of heavies would be able to pretty effectively hold off or kill a HAV without those heavies being easily blapped. Without the tank having infantry support to handle the heavies, it would be at a disadvantage. More team play is good. Making the militia starter AV fit not harmless would also be good.

What do you guys think?

splash resist mods

Not really useful for the issue at hand, which is Large Railguns vs Heavies, which are easy to hit directly.

so you gonna nerf sniper rifles too? same problem.

railgun splash radius should be taken from 5 meters to 3. if i can hit you with my slow tracking large railgun tho, you die. no two ways around it, you got shot in the face by a tank. heavies are slow, you knew that going into things. you cant arbitrarily change things cause you dont like getting one shotted by a tank when he hits you with a dome shot.

its not that easy actually hitting a dropsuit square on with a railgun turret and decreasing the splash would change things for the better.