I don't think a situation like this is on the stat weights, actually. I'll need to give it more thought, but my first guess: The thing is that, although stacking Haste above mana cap is valuable, all of your Spirit above the cap isn't very valuable. I kind of doubt that the Haste can make up for the "wasted" Spirit. Haste's stat weight would need to be well above Multistrike to make up for the Spirit that you have to put on to keep your mana where it was before. It's above Multistrike, obviously, but I wonder if it's by enough.
Also Bastion was good.