People often talk about how bad the "underutilized" HESH shell is but fewer people remember what it used to be like. Nowadays HESH spall generates in a direction normal to the plate ot hits, that is perpendicular to the plate. This is technically realistic, but due to the lacking level of detail in damage models it causes poor damage. It was not always like this, as back in the day before 1.71 spall was generated in line with the impact. Watch videos of HESH from around 2016, before update 1.71 to see what I mean. Example.
Then on the tragic day 18.9.2017 came update 1.71 "New ERA" with the following patchnote.
-"The after-penetration effect of the HESH rounds has been updated: secondary fragments are generated at normal to an armour surface and not by the direction of a hit."
Now at the time people brushed this off because HESH wasn't exactly a staple ammunition type. However, some players had found it extremely effective against tanks with heavily sloped armor, such as soviet ones. The Conqueror used to oneshot tanks with it in a way that justified its nearly 20 second reload.
It may not come as a surprise that update 1.71 happens to be the very next major update after 1.67, which added the IS-6. As we know, the IS-6 at 6.7 was one of the most egregiously busted premiums ever added, right up there with the likes of the T58. The IS-6 just so happened to be extremely weak against pre-nerf HESH that was used by tanks such as the Centurion Mk.10 which was 7.0 at the time.
I think it is hard to argue against the notion that HESH got its most decisive nerf as a direct result of Gaijin wanting to indirectly buff the IS-6 and other soviet tanks, and I would like to spread the word as I believe HESH deserves justice.
Edit: Correction that 1.71 did not come directly after 1.67. My mistake. Still, only a few month difference.