I think Draymond is easily more important than Durant on that team. Not saying he's better than Durant but Durant's skill set is made semi redundant by having Klay and Steph out there taking a ton of shots. It makes him less effective. If Draymond gets hurt, the Warriors turn into a run of the mill playoff team. They'd be good but they'd be as vulnerable to losing a playoff series as any other team.
This is why I think the Kings need to acquire players who aren't so redundant. Guys that do things that the current players on the team can't do. Getting up shots is great but playing defense, making plays for others and doing the little things that help your team win go a long way and Draymond is a perfect example of that.