The term "slackness" is a good option for your context. It has the sense of "disorganized" as you can seel below, and it is used by natives in books and newspapers, such as the Washington Post. Click on the second link I shared to check the usage of this word in real writings.

slack 1 (slăk)
adj. slack·er, slack·est
1. Not tense or taut; loose: a slack rope; slack muscles. See Synonyms at loose.
2.
a. Lacking in activity; not busy: a slack season for the travel business.
b. Moving slowly; sluggish: a slack pace.
3. Lacking in diligence or due care or concern; negligent: a slack worker. See Synonyms at negligent.
4. Flowing or blowing with little speed: a slack current; slack winds.
5. Linguistics Pronounced with the muscles of the tongue and jaw relatively relaxed; lax.
v. slacked, slack·ing, slacks
v.tr.
1.
a. To make looser or less taut: slacked the sail.
b. To make slower: slacked our pace.
2. To be careless or remiss in doing: slack one's duty.
3. To slake (lime).
v.intr.
1. To be or become slack.
2. To be inactive or avoid work: slacked around the house all day.
n.
1. A loose part, as of a rope or sail: hauled in the slack.
2. A period of little activity; a lull: a slack in business.
3.
a. A cessation of movement in a current of air or water.
b. An area of still water.
4. Unused capacity: still some slack in the economy.
5. slacks Casual pants that are not part of a suit.
adv.
In a slack manner: a banner hanging slack.
Phrasal Verb:
slack off
1. To decrease in activity or intensity.
2. To work less intensely than is required or expected: slacked off at work and started surfing the internet.
Idiom:
cut/give (someone) some slack
Slang To make an allowance for (someone), as in allowing more time to finish something.

Suggestion. More poetic, maybe.

A suggestion based on the belief that "lacunaridade" conveys an idea of "spaces" between the author's writings rather than negligence or disorganization.

as the text refers to the manner the author set down his ideas, this translation makes sense

Lacuna = a gap or space, esp in a book or manuscript

https://www.collinsdictionary.com/dictionary/english/lacuna

The citation is from a different field, but the flow pattern is similar:
The continuous and simultaneous separation and fractionation of samples by free-flow electrophoresis has both analytical and preparative applications. Nature volume 341, pages669–670(1989)

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Note added at 1 day 12 hrs (2020-06-27 01:33:08 GMT)
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Free verse is a form of poetry based on cadence rather than strict meter or stanza. The length of line is long and short, oscillating with images used by the poet following the contours of his or her thoughts and is free rather than regular. https://en.wikipedia.org/wiki/Free_verse#Form_and_structure