First off, with 1.7, blaster were indirectly nerfed through the removal of the scattered variant. Scattered blasters did about 10% more damage with no reduction to RoF, range, etc.
Rails received a MASSIVE buff. Previously, rail tanks could not even see an installation, tank, or player that was 100m away. Now they can see out to 600m, there full effective range. On top of this, dmg was increased tremendously. MLT rail was buffed from 940 dmg to 1450 dmg. With the addition of dmg mods, a MLT Sica with 2 MLT dmg mods can 2 shot any shield tank without an active hardener or heavy shield extender. The turret itself received a 50% dmg buff plus close to 60% dmg buff from dmg mods, which were previously not viable due to cost and fitting.

Glass cannon tanks are a major problem for serious tankers and ruin the fun of tanking. Even a well built madrugar can die in 2 hits to a glass cannon tank. Typically, you never know your about to be hit. Once you do take the first hit, its too late and your going to die regardless. With the many bowl maps, where there are mountains surrounding the battlefield, many tankers who would much rather fight on the field cant do so because there is always some noob who sits in the red line with a rail gun.

Rail guns are low risk, and therefore, should be low reward. BUT they have 6x the range of a blaster, allowing them to sit in the redline AND have MUCH MUCH higher dps. ALSO, rail tanks in the red line always stack dmg mods. They dont get shot at so they dont need survivability, therefore making dmg mods useful.

So lets do the math.

STD/MLT rail
3 shots 1.3 apart = 2.6 seconds and does 4350 dmg with no dmg mods or about 6800 with 2 dmg mods
NO dmg mods ==> 1673 dps
2 dmg mods ==> 2615 dps

STD Blaster
105 dmg .14 sec fire interval = 7.14 rounds per second
no dmg mods ==> 750 dps

The rail has a massive advantage and I know someone is going to comment on my rail math so here's the explanation:
Rails have a .3 sec charge up for the first shot and 1.3 sec fire interval after that. My dps calculations are based on the time interval that the tank is taking dmg. The other major issue is the factor of surprise. Most players do not know that the tank 600m away is about to shoot them. So they dont know they need to use their hardener. If they are shield tanking, one hit from a railgun makes their hardener nearly useless. If they are using an armor tank, they have a few seconds to get behind cover before they die. Note that a rail can 2 shot a madrugar, meaning you have 1.3 secs to get that slow tank moving and behind cover......it takes 3 seconds to turn 90 degrees

So why do we have glass cannon tanks? because you can spend 80k isk on a redline rail tank and destroy tanks that cost 300-450k isk with ease......how is this balanced?

My proposal:
1. Nerf rail dmg by a minimum of 25%
2. Limit tanks to 1 damage mod
3. Nerf dmg mods to +20% dmg

Other considerations:
Nerf Shield and armor hardeners as follows:
Armor / shield
MLT 25 / 40
Basic 30 / 45
Enh 35 / 52.5
Complex 40 / 60

Leave cooldown times as they are.

A tanker should have substantially more survivability than a non tanker.
This is no different from a player with 20mil sp into infantry using a proto suit having an advantage over someone with 0 sp into infantry in a mlt suit.

Make tanks worth specializing in. Currently, putting millions of sp into tanks helps, but you will still die to the noob with 0 allocated sp sitting in the redline with mlt rail and mlt dmg mods.