I can't speak to that particular example as I'm not aware of VOY being particularly criticized for that. As an example I can speak to - the softening of the the Borg - my feeling is that VOY encountered them with such greater frequency and intensity than the TNG folks did that there should have been more significant consequences -at some point-. Nevermind how "Unimatrix Zero"(?) made (even partial) assimilation look like a cakewalk. The poster who noted that VOY never appeared to suffer significant damage nor casualties from any of its multiple encounters with the Borg nailed it rather well IMO. Ironically I thought the whole point of the end of "The Gift" was that Kes had essentially pushed VOY out of Borg space, at least for the most part. Clearly either she didn't do that, the Borg underwent a massive expansion immediately afterward, or even the areas that aren't considered part of Borg space are nevertheless crawling with Borg, which makes little sense to me.