There is nothing wrong with certain champs being easier to play than others, if you look each champion has their own difficulty. This helps newer players in a lot of ways. Besides, we're talking about a tank here. They're not supposed to be easy to kill in the first place. If you can't deal damage to a tank, then obviously you need to build penetration. But when it comes down to it, their role is to take damage. Also, with warmongers, pretty much every champion with over 3000 health can stand there for a few seconds and come back with full health. Easy counter to that is to make sure garen or anyone with warmongers keeps taking damage so they can't come back with full health. There are sooooo many ways to work around this.