I had a few hours to contend with my Druid yesterday and decided to equip him with a similar spec I had before the patch.
Going heavy into balance up to moonkin form and then dipping into resto to get the nature's swiftness talent left me without the ability to try new spells but gave me a setup that is very similar if not close to identical to what I had before the patch.
The advantage of this was that I was able to 'feel' the difference between my old moonkin and my new moonkin without being biased by things like starfall or the new talents of upper tiers.
Here's a list of somewhat random observations while playing my moonkin at lvl 63 in Zangar.
1. Mana regeneration is hardly an issue anymore. Where I previously had to sit and drink and rely heavily on innervates after a few pulls I am now happily coasting along from mob to mob without too much downtime.
2. XP gain in Outland has indeed increased. From what I see I gain a fraction more XP but the XP requirements per level have been adjusted downwards quite a bit. A normal session of a few hours on an outland character usually netted me 5-10 bubbles at most to my next level. Now I am looking at approximately 15 bubbles for the same time investment. So while I don't have the actual figures here I'd say we're looking at about 30-50% less time needed to hit the next level.
3. Spell damage appears to be about similar to what I had before but the moonkin seems a lot more crit-happy than it was resulting in a lot more ability procs and indicating that stacking some more crit on a moonkin could be worth the investment.
4. Clearcasting from the new passive omen of clarity procs very consistently on about every 3rd spell I cast. I also experienced a clearcasting proc over abilities that I cast on myself (mark of the wild, thorns etc.) which I am fairly sure is not intended. I will further test this to see.
5. Roots indeed work indoors now taking away a lot of my hesitation to wander into caves and dungeons as a balance druid. While it looks a little weird to see giant roots shooting out of a solid stone floor it definitely help to have the ability around indoors.
6. Driving myself OOM on a few occasions on purpose to see how I would regenerate did indicate a somewhat different approach. Previously I had to throw up omen of clarity and go whack something in the face to get more mana, now the mana regeneration is quick enough to allow for a root->swarm rotation resulting in less risk. Clubbing things still helps but only results in clearcasting procs, which are nice but not necessarily a reason to want to go toe-to-toe with enemies.
Overall the Moonkin / resto druid combination now feels a lot more like a caster that is trying to avoid melee where previously I would regularly 'bird-tank' things in order to regenerate mana or while dealing with OOMness.
While I was not able to try out most of the new spells abilities in higher tiers I can definitely say that the moonkin 'fun-factor' has increased significantly but primarily on the merit of better mana regeneration and more crits.
Still so far the balance tree looks very interesting and there's a lot of talents in there that will make it difficult to choose between when you run out of points to distribute.
As long as I don't run into significant issues with my druid further up in the talent tree I'd have to say that the work blizzard did in the balance tree is very satisfying thusfar.