While I understand the point you’re making (and even agree with it a bit) on how the Tiger II is a bit easy mode, some of this is just flat out untrue or wrong.
The weight and horsepower of the T26E1-1 provides it with 10.02 hp/ton. Yes, it is quite low, however you ignore how the Tiger II (H) is also very underpowered and is barely better with 700 horsepower and 69.8 tons of weight, giving it 10.03 hp/ton. Neither of these tanks is particularly more mobile than the other.
Sheer engine power does not matter. It’s only important when you also have information on the gearing, weight and more minor characteristics like the length of the tank that it becomes a more meaningful statistic. The M4A3 (76) also has the Ford V8 500 horsepower engine and its mobility is quite good, having acceleration that is on par or even superior to the T-34-85 depending on the speed.
Due to the fact that the T26E5 is a lot lighter (46.4 tons), it ends up with 10.78 hp/ton, and as all the Pershings currently have great gear ratio distributions, it ends up being more mobile than the Tiger II (H), even if not substantially.
It really isn’t when you consider the characteristics of both tanks.
The T32 has an identical turret ring diameter to the M26 Pershing and the M4 Sherman of 69 inches (175.26 cm). While the turret is bigger on the outside when compared to either of those tanks, thats mostly due to armor thickness as the inside really isn’t. And unlike those tanks, the T32 is dealing with rounds that, with projectile and casing combined, are roughly 50 inches long (127 cm, over a meter long).
The Chieftain uses a significantly bigger turret. On top of that the APDS rounds it fires are actually lighter than the typical AP rounds fired from the T32, and improvements to propellant charges likely means that the Chiefains requires less propellant to get its rounds to a high speed when compared to the T32. Theres likely other stuff I’m missing that could explain further why the Chieftain would reload faster and the T32 slower.
That doesn’t mean the T32 can’t have a faster reload. After all, Gaijin has and will continue to use reloads as a soft balancing factor.