If I had just one thing to say about the level 60 to 70 bracket it would continue to be that Death Knights should not be allowed to tank until at least level 70. And quite possibly not even then. I did hit level 70 yesterday morning but there were times along the way from 60 to 70 where I was seriously questioning whether I would ever see 70. While I did quest over the weekend in Hellfire Peninsula (I never made it out of the zone before 70), the dungeon finder would pop quickly enough that I'd rarely get to finish one quest and move onto another before I'd be pulled into a group. Which is pretty awesome in and of itself, but one thing it opened my eyes to was the amount of people who have recently created DKs. I'm not normally one to generalize about a class like this, but I can definitely see the point many people have long been making about the class now. Starting at level 58 and then generally moving strait into Outlands does not give you the time it takes to really learn how to play your class. At that point in your play you really only know the generalities of the class and its rotations and you aren't in a position to tank well. Which of course isn't to say I didn't actually see a couple good DK tanks here and there, but most of what I saw was just abysmal.
My general dungeon experience over the weekend was that I had a DK on about 60-70% of my runs, with a majority of those not being able to hold agro on groups. A great many of them didn't drop Death and Decay or use Pestilence to spread their diseases and I'd end up healing most of the party. I got through it, but what particularly galled me was that most of these tanks were so completely oblivious to anything but themselves that they wouldn't pay attention to my mana situation and would run off to the next group while I was still drinking. In a lot of those situations I'd be able to catch up in time and blow a swift mend cool down in time and give myself an opportunity to heal them up. But on many other occasions it would result in a wipe and despite my stern lecture to many of these tanks to pay attention to the healers mana they'd generally do whatever it was they felt like doing regardless. It didn't help matters that of all the tanks, DKs tend to take more damage and require more healing that others, so needless to say it was a relatively stressful leveling experience over the weekend.
It was strange because all of my experiences prior to this character were leveled without the benefit of the new LFG system. So I have general expectations that I should be in a particular zone by a specific level. I found it very interesting that I was level 68 and still in Hellfire Peninsula. Between dungeon runs and battlegrounds I earned so much XP that it simply didn't matter whether I moved on or not. Completing quests, I think, is now more about earning gold than earning XP and in that light it's probably better to hold off on completing quests until level 80 (if you can) when the pay outs for the quests increases.
In so far as tools go, Feral has everything it needs by level 60 to be quite successful, whether you pick up Berserk or not. I didn't, and chose to put my points in elsewhere as I feel Berserk is best left for level 80. All of my talent points post-level 60 went toward gaining additional damage, so I filled in a few talents in the feral tree, but also putting points into the Resto tree as well. Feral has always been the best leveling spec - as far as I'm concerned - but from level 60 on it truly shines. A great ability to dish out DPS, stealth, heal, and greater movement speed all add up to a great package. And the gear you generally get in Outlands only makes it all the better. Being able to now fly in Outland immediately at level 60 makes questing and leveling fantastically easier as you can avoid agroing everything while traveling from one area to another by simply flying over their heads. Simply fly to where you need to go, then drop down near your target and immediately fight. Of course this depends on whether you've put points into Furor or not. If you did you'll switch into cat form and have a full energy bar, otherwise fighting like this will become a bit tedious.
Level 60 is also the beginning of the best period for Resto spec as well. At level 60 you get Wild Growth, which makes healing runs tremendously easier. The only healing tool left to learn that you won't at level 60 is Nourish. Which isn't a big deal as you can just continue to use Regrowth as you've been using it since your earliest levels. From level 60 on all of your talent points should be making individual heals better or cost less mana making you an incrementally better healer. But you can and will run into mana trouble if don't continue to exercise the healing discipline I've mentioned previously. Generally if you only have to heal the tank and use wild growth to heal intermittent group damage you should use very little mana at all. Mana problems, and by that I mean getting down to 50% or so, should only happen if you have to use several regrowths on multiple group members, and also rejuvs and wild growth during any fight. Even on those fights where I was having to heal everyone because the tank couldn't keep agro I was able to keep up my healing throughput and never ran out of mana. When Innervate was available I'd use it and keep on moving with the group, but I would have to drink every now and again under those conditions. My experience might be different from others however, as I already have another Resto Druid and have had years of raid and dungeon healing experience. So I'm fully aware of the stats I need to pay attention to. I carefully weighed all of my upgrades to maximize my spell power and mana regen. If you were in similar situations as I found myself in but hadn't paid all that much attention to your mana regen you might find yourself running out of mana, or not able to keep heals up on everyone during chaotic fights.
Once I hit level 70 I abandoned the Outlands and moved on to Northrend, where I now get to figure out the new quests all over again.