Not in absolute terms, of course, but in relative terms definitely. Casablanca is a brilliantly written film and To a God Unknown is a brilliantly written book, however, what makes the movie brilliantly written and the book brilliantly written aren't the exact same qualities.
When I say Torment's writing isn't a good as a classic novel(say, Crime and Punishment), I'm talking about how the game and novel harness their respective mediums in order to tell their narratives and expound their themes. Game writing and design still has a very long way to go before games can be fairly and positively compared to other mediums.