"haste cap" is 1270 haste.
This does not mean that Haste is worthless afterwards, it'll still be better than Crit for like.. always. (tested with 565 Crit rating and 1900+ Haste rating and Haste STILL won)
Haste is ~1.5x as good as crit (depending on your current gear, etc.) so you better take the Abyssal Rune than the Sundial.
Now... to those trinkets... both are rather crappy for Elementals.
If you're already having the Totem for Emblems then you CAN take the
http://www.wowhead.com/?item=48722, although, as I said, it's rather crappy for Elemental... it might be okay when you're not having a Shadow/Boomkin in your group, so you'd better exchange another Hit-item for Crit/Haste/Spellpower, so you'd be closer to hitcap.
I don't know how often you're raiding with a Shadow/Boomkin... but if you often have one in your Pugs, you might first get some T9-items instead of the Trinket.