Seemingly the only tank-specific change on the new sandbox server, WG has added AP shells to the derp guns on Type 4/5. Previously the said gun only had HE and HESH; only the 14 cm had access to the AP shells. Now the 15 cm derp gun gets AP shells as 3rd option. It's the only gun in the game to have 680 alpha, and it actually has surprisingly good shell velocity (for that kind of gun). Other than the AP shells, the guns are unchanged (aside from changes to the HE mechanics), and the tanks themselves haven't been changed in any other way.
Since HE spam isn't viable anymore, the Type 4/5 derp, which is already abysmally bad, will become even worse. WG giving them an AP shell to give them an option to fight against anything with armor makes sense. I actually like the idea – it seems like WG wants to rework the Type 4/5 derp gun into more a "regular" gun, that still stands out from the other gun by having HESH as premium instead of AP, or APCR/HEAT like most guns have. Think like Conway's big gun, but on a heavy. The concept is still tricky to balance, but I think it's at least much better than a pure HE based gun on a super-heavy. It's probably the best option aside from straight up removing the gun, which what I personally would've done.
However, the gun is still way too awful to be worth anything, as it still has the horrendous 0.5 accuracy, worst DPM out of all single shot heavies if AP is used (same reload as E 100 but with 70 less alpha), and the pen isn't good enough, especially considering the lack of higher pen premium ammo, and poor gun stats. Type 5 with the gun is completely incapable of fighting some other super-heavies with the gun, as the HE doesn't do much and pen is just too low. 240 pen is much better at tier 9, though, so the gun could be pretty hilarious on Type 4, and at very least it makes the stock grind much less horrendous as there's now a non-premium alternative to the crappy 900 alpha 75 pen HE shell. Also 680 alpha at tier 9 is pretty insane for a tier 9 heavy.
This gives me hope that WG is finally trying to abandon the whole concept of Japanese HTs being pure HE slingers, as a super-heavy designed to purely HE spam is practically impossible to balance. Abandoning that terrible design could mean they'd consider reworking them into something better and more interesting, but maybe I'm being too hopeful there.