The only time I like really large dots is on my dedicated short range weapons.
Like my MP5k for instance. Or even perhaps a scattergun.
My MP5K has a 5 moa dot by Millett, but the gun having a 5.5 inch 9mm barrel, is not intended to shoot 150 yards away, so having a large dot makes target acquisition fast, and at closer range, the large moa dot doesn't have to be as specific (point of impact) as long as it's in the zone. Not only that, but a larger dot covers more of the surface area, and at longer range can totally obscure.
I'm having a difficult time trying to put my thoughts into words.
I guess what I'm trying to say is, small dots are usually more capable at intermediate distances than large dot sights. And large dots work better for close in work. Especially in speed and multiple target acquisition.