So called bloom isnt THAT bad, i think it is part of weapon balancing. The game clearly writes out which guns are meant for what ranges. For example you have the M4A1, close range, higher bloom mid-long range, whereas M277 would have a lower bloom but lower ttk. Running and gunning would cause you to feel the full effects of "bloom", which you will have to change your attachments accordingly.
i personally have 2 builds for my M4A1, one for short-fast paced, near 0 distance engagements; like the city maps in the breakthrough game mode. Blue laser, angled grip, converter, short barrel, 20round fast mag. And the other one, a stubby grip, basic mag and barrel, suppressor, 2.5x scope, blue laser meant for close-mid range engagements, these attachments all change how the gun behaves, and how bloom is affected.
Another thing is tap firing. With what i have just established with guns(and its attachments) filling their specific roles and playstyles/ranges of engagement, tap firing is immensely important when you are engaging someone out of the range of the gun's designated capabilities (or that you have assembled it to be). Depending on how far they are, you want to do small bursts, or even semi auto.
[Tap firing/Burst firing also resets the build up of "bloom". Imagine bloom as a cone in front of your muzzle- where your bullets travel in, and the longer you hold fire, the bigger the cone gets.]
the game has movement penalties for "bloom" so that the attachments can actually work, and it rewards you for using the right combination for your own playstyle. For example, if youre running and gunning, a laser to control hip fire and hence reduce the bloom effect is important.