Indeed, missions to ice worlds are less challenging in terms of surface conditions, though time in flight is at best comparable.

In The Killing Star by Pellegrino & Zebrowski ice-worlders are dominant in the Universe over terrestrial type surface dwellers (and sterilize emerging up-and-comers accordingly). While this concept clearly predates the Dark Forest hypothesis (in fact, I have little doubts that Liu Cixin simply adopted it from The Killing Star), and ice-world aggressors look like one of the most clever implementations of Great Old Ones-like eldritch abomination from SPACE in science fiction, P & Z essentially ignore great hindrances, that surely would have arisen on paths of technological progress inside ice worlds, which are isolated from the outer space. It's a pity.