This construction is puzzling me...

You need a passive--
"they were easier TAKEN advantage of"

Recast the entire last clause as 'when it was easier for powerful men, who knew they could get away with it, to take advantage of them'

Persephone and I are on the same page, but I'd make a slight additional change and say, "How about a return to the days when women were in such vulnerable and inferior positions, that it was easier for powerful men, who knew they could get away with it, to take advantage of them?"

Note the pronoun confusion in the last example, though (they/them).

A more invasive recasting of the sentence might go something like:

"How about a return to the days when women were so vulnerable that it was easier for powerful to take advantage of them with impunity?"

Anonymous was me, sorry....

Speedwell's phrasing is nice, but would be a little better without the first comma -> "How about a return to the days when women were in such vulnerable and inferior positions that it was easier for powerful men, who knew they could get away with it, to take advantage of them?"

And this is what happens when people reply at the same time. Speedwell's latest attempt is nice, but there's an adjective desperately seeking a noun there.

(cries) I didn't actually miss that but I didn't want to post four times in a row.

Dyske, I wish we had a preview....

You could say...

"How about a return to the days when women were in such vulnerable and inferior positions, where they were more easily taken advantage of by powerful men who knew they could get away with it?"

it's a little more casual than the sentence structure persephone gave althought that is very correct as well.

I don't really like this last construction. There's another thread discussing the (mis)use of "so" as an adverb and I believe "such" is used the same way here. Remove some of the extra verbiage and we're left with: "How about a return to the days when women were in such vulnerable and inferior positions?" That's not a correct sentence, IMO. I think allowing the second clause to be independent of the first breaks the sentence.