I sorta understand what you mean. But since I started playing gnar, he's been very generally untanky. After looking at the current PBE changes, the idea of him receiving a thirty health decrease is a bit much. I realize this also gives him room for early level 1 fighting disability. And I also realize Gnar is strong in the top lane meta. However, a couple tanks such as
tend to shove gnar out of lane frequently, and give him a wide berth. Even if someone resolved to try poking these champions down, gnar's only chance against these lockdown/heavy cc'ers is to probably devote a lot of time poking down with q before making a jump flash play to attempt and lock down their opponent.
I realize Gnar is strong, against many, many champions in the league of legends right now, especially in the top lane. But I also realize that many people don't play the three selected champions I named earlier. All I wanted to mention is that while Gnar does have many options, perhaps the right way to attend him, isn't the reduction of his ability to stay in the fight. Since, once he becomes mega gnar, being tanky and enduring the coming blows is what drives his purpose.