Some specifications leaked:
lens construction: 20 elements in 16 groups
size: 88x151mm
filter: 82mm
weight: 854g
mfd: 0.27-0.73m (magnification 1:51 to 1:53)
AF: VCM motor
I agree. It seems as though Samyang is trying to compete with Tamron by making “extreme” zooms, but they come with some serious issues and fall short in certain areas, such as coatings.
I preferred it when they focused on making good, fast and lightweight prime lenses.