Other than that, try getting rid of every Haste point you possibly can and dumping it all into your preference of Crit and Mastery.
Yeah, Haste *is* still bugged with totems atm <shakes fist at Blizz>, but I'm one of the shamans who's seeing good results from weighting Haste in T15. When I first reforged to Haste a few weeks ago, I couldn't get enough Haste to hit the breakpoint I'm currently gearing for (Riptide), but I did have the ability to overshoot the 3764 HST/HTT breakpoint. I ran with just over 4k Haste, and I got my extra ticks every single time.
You may say "yes, but the 240+ Haste you added to your gear is lost throughput you could have put somewhere else if you didn't have to overshoot the breakpoint in order to account for totem inconsistency" but... /shrug. The extra Haste helps shave down cast times. I know it's not a huge reduction, but every millisecond counts on Tortos, for example, which is what we were struggling with at the time. Meanwhile, the extra healing from my totems was *highly* beneficial.
Back in T14, only those who were in mostly heroic gear could afford to hit & overshoot the 3764 breakpoint. Haste stacking wasn't worth it for all but those who could get that gear, and of course even then it wasn't necessarily something every rest shaman was interested in.
I've had a few important upgrades since first managing to squeeze enough Haste out of my gear to hit 3764, and I can now hit 5676 with relative ease (would have been nice on Tortos, grumble grumble). A few more upgrades, and I'll be able to get to 7613, which will be huge (Healing Rain).
Meanwhile, my casting times are now noticeably faster. Not so important when you're standing still, but in any fight which requires movement, having the ability to squeeze in a heal before being forced to move can be *huge*.
I plan to play around with dropping AS at some point too, to pick up EM to supercharge my HTT for specific burst-healing moments. I'm sure there will be certain fights where that's superior to constant +5% Haste.
One thing I will mention about the OP's Haste - s/he isn't actually *hitting* the Haste breakpoint s/he is aiming for (the 3764 breakpoint with AS and +5% spell haste buff for 2 extra ticks of HST, which also confers 1 extra tick of HTT). Either invest more into Haste so you're well above the 3764 breakpoint (which, since it's a totem breakpoint, it's crucial that you overshoot) or drop as much Haste as you can (the breakpoint below 3764 is 871, and it's for Earthliving Weapon, which interacts reliably with Haste so you don't need to overshoot it, though in practice it's likely impossible to reforge out of enough Haste to hit 871 on the nose), including being sure to take EM over AS in the talent tree (then macro EM to HTT and possibly Ascendance).
edit: something else I wanted to say is that every resto shaman should consider aiming to overshoot (lol) HST breakpoints once they get their T15 2pc.