Thornmail is a very underwhelming item, especially in this patch. It has a gold efficiency of 79.01% on its base stats, and what's worse, it doesn't make up through its passive. In fact, Thorns is one of the weaker passives in the game, doing meager reflect damage upon attackers. Except for its lackluster base stats, the only other reason why you would consider buying Thornmail is the grievous wounds debuff that is applied against basic strike attackers.