I can count three from just this angle.
Almost all toys have those specks when they're painted and guess who can even see them? Shit like that is why people take photos here, someone points out flaws like that and the posters say "never noticed it before"
And your example for doom is pretty shit, because most of the "lumps" you see is just the sculpt and the various washes just making it look messy. Washes in general don't produce "lumps". It's airbrushes and the spray masks that they use that do that, with the spray masks being the main culprit since paint flakes off the mask. It's unavoidable, especially since every figure that uses airbrushing and spray masks have it. Even these Warhammer figures have them, which you likely haven't noticed because you don't own them, don't look at macro images often, or no one's told you.
How to avoid them? Be a cheapass like Bandai and Mattel, relying mostly on colored plastic that makes them look like cheap models. Obviously, they still need to add SOME paint, like on the borders of this armor and you can see on the right shoulder some actual lumps, likely from specks clumping together.>>9312736
As this thread has proven, most people don't understand how toys are made and are pretty hypocritical to boot. There's a lot of cheapo figures with ACE paint jobs at a cheap level, like DCC's, NECA, and even McFarlane (their CoD, Dune, and Borderland figures were well done). Diamond usually has very good paint as well, but i really haven't checked out their figures in like 2 years.