They have pulled down the tint of the glass a bit in the release, so it shouldn't be *that* dark now as it was before. It is however a intended balancing function as to let Iron Sights have a function as well.
I mostly use the Reflex Sights on close range weapons like SMGs where I don't expect to shoot many enemies at a distance, where the tint can make it harder to see them, the reflex gives a better peripheral vision around the weapon when aiming down so close enemies are easier to see. Iron Sights I use mostly on weapons that I want a bit more flexible on medium range and short like the SMLE or STG, since there is no tint on the sight it is easier to see distant enemies, while also not having a too affecting zoom so that I can still easily aim down and shoot at close range enemies. And then scopes on longer range weapons like some LMGs/MMGs (Air Sight in the case of MMGs) or the Gewehr, where I just expect if a enemy gets too close I am screwed with the primary anyway.
