The E8 has the role of an upgunned sherman, it completely wipes the floor with the Ost and OKW PIV's thanks to the added armour and penetration which the regular sherman struggles to do. Nothing to do with rng here, it does that quite consistently.
It was already overperfoming for the cost which is why it was upped in price shortly after WFA release. Go read the old threads if you struggle to understand why making the E8 even cheaper is a bad idea.
It was overperforming for cost because it was a callin vehicle. Now that it is built from major tier, it needs a cost/ role reevaluation.
I'm going to compare the M4A3E8 and the M4A3 Sherman now, to show why I believe the E8 is not performing up to its cost, when compared to other USF T4 units. I will then argue why I believe it should get a rework to become an 800HP unit.
http://www.coh2-stats.com/vehicles/m4a3_sherman_mp
http://www.coh2-stats.com/vehicles/m4a3e8_sherman_easy_8_mp
Speed:
As you can see from these stats, the base Sherman has a slight speed advantage over the E8. Its not much, though, so I will consider it negligible. This means that only the weaponry and armor is important when comparing these two tanks.
Armor:
The E8 is indisputably better with 215 frontal armor, giving it a chance to bounce PAK and Shrek hits. However, the M4A3 and the M4A3E8 both share an HP pool of 640. This means that both will die from two shots from heavy AT sources, and die at relatively similar rates from all high pen weapons.
AT:
The E8 is a better AT tank. It has an average of ~60 pen better than the base Sherman, allowing it to penetrate anything short of a Panther reliably. The E8 is also more accurate. The M4A3 has a .4 second faster reload time, making it a marginally higher DPS tank vs. lighter armor. This is really only important when flanking and fighting light armor.
AI:
The M4A3 is a much better AI tank. It has access to HE rounds that can regularly wipe squads, and deal heavy mp bleed. The MGs on both tanks are the same, and both deal good, reliable damage.
Price:
The M4A3 is 110 fu, while the M4A3E8 is 140. This makes the M4A3 significantly easier to replace and maintain in the field.
By looking at these stats, we can see that the M4A3E8 is a great tank that is well rounded and can deal with all targets. However, the base Sherman is perfectly capable of soft countering armor, while also being more effective vs. infantry. USF has access to the Jackson in T4 to deal heavy AT damage to all targets, far more efficiently than the E8 can. The E8 however, merely does an OK role at both jobs, while being more expensive than each and not necessarily more durable in the lategame.
This is why I would argue that the E8 should get a small armor decrease to 160, and get an HP buff to 800. By getting 800 HP, it would be more resilient to Heavy AT (3 rounds instead of 2), while remaining equally resilient to medium AT with less RNG. Currently, you end up paying 140fu for a unit that may not end up being any more resilient than a base Sherman, and that is not a gamble USF can always make due to their heavy MP bleed.
Why less RNG? A 640 HP E8 can die to 4 Pak rounds if all pen, but there is a chance for bounces. If it bounces, it can survive 4 rounds (usually the case), and maybe even survive longer than that if lower pen weapons like Pshrecks are being fought. An 800HP 160 armor Sherman will have more survivability in the lategame than a base Sherman, while not relying on RNG to fight lower pen weapons.
By giving the E8 more HP, we give it a real role (damage soaker) and also make it less reliant on RNG, which is something we should strive to minimize when it has 0 bearing on player skill.