Hit Rating is hard to come by on tanking gear as a Druid, though we do have a few options.
1) Jewellery. If you can make up crit reduction or armor elsewhere, jewellery is not a bad place to get some Hit Rating. Especially the new
[Brooch of Deftness] is a damn good aggro item because of the Hit Rating AND Expertise. There's also stuff like
[Frayed Tether of the Drowned] and
[Band of the Abyssal Lord].
2) S3 Arena gear. A bunch of pieces have a nice bit of hit rating on them, and if you wear 2 pieces, you get the 35 resilience set bonus which is a good chunk of what you need for crit immunity.
3)
[Nordrassil Feral-Kilt] and
[Thunderheart Leggings] both have a decent amount of hit rating.
4)
[Boots of Natural Grace] are very good if you're a leatherworker pre-BT.
5) If you use a
[Relentless Earthstorm Diamond] you should be using 2 x
[Glinting Noble Topaz] to make up the yellow gem requirement.
6) Sacrifice mitigation, wear a bunch of Rogue items with hit rating in lieu of more bear oriented high armor items.
Druid threat is already solid despite our not-as-good-as-Warrior itemization when it comes to aggro stats (by which I mean Hit Rating & Expertise, not Str/Agi), which is why I guess they won't give us much Hit Rating / Expertise. Imagine if all the Intellect on our set pieces was Hit Rating and T5/6 Pants had Expertise O.O
Personally, I never focussed on Hit Rating. The only Hit Rating I had for a long long time was purely incidental (on Nordrassil Kilt). Only recently did I acquire Brooch of Deftness solely for the aggro producing stats on it. And so far (5/6 ssc 3/4 tk) I've not ever had threat issues on a boss encounter that I can remember.