I've long anticipated this retrospective of the artist's work, hoping that it would make (i) _[accurate]_ judgments about him possible, but greater familiarity with his paintings highlights their inherent (ii) _[difficulty to understand]_ and actually makes one's assessment (iii) _[also difficult]_

Blank 1:
A. modish means about style -- no evidence in the start of the sentence regarding style
B. settled means to settle a debate -- this could match my prediction of "accurate", in terms of settling judgments about him through the use of his retrospective art. Keep this for now.
C. detached means separate or disconnected -- no evidence to support a "detached judgment", and does not make sense.

Blank 2: -- the word "BUT" indicates a shift in the sentence. The second half will oppose the first half.
D. Gloom means darkness or depression -- does not match my prediction, nor explain how "gloom" could cause not make a judgment possible. If it had gloom, we could make a judgment that he was depressed.
E. ambiguity means having more than one interpretation -- could match my prediction, making it more difficult because of multiple interpretations. This also explains how a painting being ambiguous would make it hard to make a judgment. Keet this.
F. delicacy has a couple of definitions, none of which fit here. Nor does being delicate mean making a judgment would be hard.

Blank 3: -- the word "ACTUALLY" indicates blank 3 should match the idea of blank 2.
G. similarly equivocal means also ambiguous -- because of the word "actual", this fits as a match.
H. less sanguine means less happy -- does not fit with "also ambiguous" which is what the sentence requires.
I. more cynical means more critical -- does not fit with "also ambiguous" which is what the sentence requires.

Answers: B - E - G

Hope this helps!