Games : Haste Soft-Cap for 2H Frost DK

After reading several Guides I stumble upon this article where a cap of 3686 haste is mentioned.

According to icy-veins Haste weights more than multistrike till BiS. But I wonder if there is a soft-cap after which crit or multistrike becomes more viable ?

And how does this effect the Procs of the Legendary Ring and T16 ? In fact I mean can there be too much haste so it gets ineffective according to the limitation of the procs ?

Thanks in advance for your replies.