I'm fairly happy with progression. I changed up my team at the very end of TBC, actually my mage and boomkin were still 69 on the 13th and mage still had on that gold tunic that EVERY caster gets at level 60. After a day of questing they had hit 70 and my other 3 (Tankadin, Resto shammy, Elemental shammy) were still mid 70 with no upgrades.

UK - FIrst boss on the 3rd try (add /target Frost Tomb to cast big-bang macro, face dps slightly towards each other, drop fire elemental totems and rock out)
UK - Second boss on the 3rd try (forget what's said on WoWWiki, nuke the caster guy first, the melee will be almost dead by the time you wear through the caster with his 50% spell dmg misrate)
UK - Third boss, 7 tries still alive (though I just learned from reading around that he only silences the casters for 6 sec if they're actively casting when he roars, with that knowledge he should die next time)

TN - Tree boss on the 3rd try (I grouped up dps on tank, just behind him, doesn't seem to produce shards there and if they do you can see it and move then easily)
TN - Telestra, 8 tries still alive (no idea here, I think I'm suffering from AOE dmg post-whip because when I box she slaughters everyone FAST and when I've solo healed or tanked no one else seems to get hurt very bad)
TN - Electrical shade guy, 1 attempt and I let the rifts stay open too long and got overwhelmed at 30%. Very doable though, nothing special here.
TN - Last guy, haven't boxed him yet. Some say he's impossible, others say he's very doable.

So, given my crazy crappy gear on 2 toons, and only half crappy gear on the other 3 I'm pretty happy with how things are going. I solo-boxed the next 2 instances, Anjol-whatever, and from what I remember they seemed pretty boxable though I'll need to be at least 73 and get SOME gear to help out. My main issue for most fights is fighting stamina. Particularly my boomkin goes OOM to fast, need to get some gear and work on a more efficient cast rotation or something. I'm also having mana probs with my resto Shammy but I need to go back and take her off her PvP spec.