Movement speed increase is nice. In addition to Stampeding Roar (which can be used in either Bear or Cat form), you have Dash / Tiger Dash (depending on talents), and if those are both on cooldown you still have the ability to simply shift into cat form and take advantage of it’s built-in speed boost. In the outdoor world, you can shift into Travel
Form, even while in-combat (although there is a speed penalty). When you are running through mobs in Travel Form, you don’t have to worry about being knocked off your mount. Being dazed will slow you down but it won’t shift you out of Travel Form.
Stealth is amazing. Some other classes have the ability to go invisible obviously, but this is a no-BS implementation similar to rogues.
Fall damage reduction in Cat form is pretty handy. There are plenty of times when you can survive a fall by shifting into cat form, and survive even longer falls if you layer barkskin and potentially ironbark on top.
You also potentially have access to Flap while in Moonkin form to slow-fall, if the fall damage reduction while in Cat is not enough. Never have to worry about being ported to the wrong Dalaran, etc.
Bear form itself is basically a no-cooldown semi-turtle form. If you know you are about to get hit by a mechanic, then you can just shift into bear form. You can even Barkskin+Ironbark+Bear Form. This allows you to cheese a lot of mechanics that would otherwise one-shot you.
Typhoon + Mass Root is a personal favorite, when a tank sucks and I pull healing aggro on trash.
The amount of quests that are potentially made easier by being able to interact with objects while still in flight form is large.
Being able to cast HoTs like Rejuvenation while on the move as a Resto Druid is amazing, although we are currently more reliant on plant-and-cast Regrowth spam than we have been in a very very long time.
The focus on HoT based healing itself is unique and fun, and forces you to be very proactive with your healing (whether that’s good or bad depends on you), but also allows those HoTs to keep ticking while you do other things.
You can switch roles while keeping most of the same gear (weapon being the biggest exception if you are switching between Intellect and Agility). It can be nice to switch roles and already have good gear rather than gearing a 2nd character.
While not having lust/hero could be seen as a negative, it’s also nice to NOT have that responsibility. Same with NOT having to interrupt, especially after the upcoming Skull Bash changes. No one bugging you for summoning stones, or lock rocks, or mage portals, or mage food. You get to just chill and focus on your job.