I have been using the enchant on my Enhancement Shaman and i really love the heal when it proc. That stuff give a lot of survivability for a class as squishy as Shaman.
Only if you’re not a good player.
We have options. If you know how to use them properly, you won’t “feel” squishy.
Also, to your OP, I’m pretty sure Crusader doesn’t work past 50.
If it really doesn’t work, i will have to find some alternative then 
Not trying to be snarky, but if you think Enhance Shaman is that squishy, you need to learn to play a little better.
Tighten up your rotation and learn where your healing and shielding options are and when to use them. Enhance can be real killing machines when you have all of your abilities under control.
That is true, it just i like having the free heal even if i get good at it and i mostly like cheesing stuff. The Cheesier the better for me XD.
Not trying to be a jerk but ways to heal/avoid/mitigate damage.
Healing Stream Totem
Healing Surge synergy with Maelstrom Weapon (literally an instant cast heal at 5 stacks)
Spirit Walk (apply a slow and run)
Astral Shift (very good mitigation)
Capacitor Totem (stun those yo)