So I took a trip through the starting Cata HC's today (mainly for chaos orbs so my tailor alt can make bags), and it wasn't an easy ride. (ilvl 465 with alch stone and SBT/AG/EM/PE, using the neverending alch flask and 300 agi food plus drums/runescroll II in some fights)
I cleared all of the starting instances, although I had to skip Corla in BRC (% hp dmg mechanics on her adds) and do an ankh run across the bridge (no Raz) to the forge (thus activating the teleporter). Luckily Raz still appeared to clear the mobs around Obsidius at the end...who is also a tough boss but earth ele helped keep the adds off me for a bit. Other tough moments included Ripsnarl in DM (ignore adds until fog phases), the croc in Lost City (blow CD's and hope for the best) and Setesh/Ammunae in HoO (strangely enough the water guardian is fairly easy now if you blow all pets/CD's and Rage a few seconds later then use /petattack macro when the water bubble comes). Erudax in Grim Batol is a tough one too, but if you save some CD's for the adds (I rotated sprint, ascendance and EM) it's ok, although he does have a tendency to knock you back with the feeble body debuff while you're chasing them.
Generally though, you should be alright against most bosses if you have all your CD's up. (it also trivialises the previously-tough trash packs in most instances, although some can still trip you up)
Trolls are out of the question for now. I did manage to kill the eagle in ZA (just) but the lynx requires much better gear due to high dmg output, the dragonhawk has way too many adds and the bear will always be impossible as he still uses his charge (debuff bang 420k oneshot). This also means that the last boss is impossible if you get bear/eagle combo, so you're rolling the dice just by entering. Didn't try ZG or the HoT's, won't be trying until better geared.
---------- Post added 2012-10-20 at 12:41 PM ----------
Oh, and probable nerfs on the horizon too so I'd get soloing if I were you:
Originally Posted by Blizzard
What about shadow priest off-heals? They are out of control atm. The utility they bring is grossly op.
Hybrid off-heals are something that we're concerned about in general.
Wanted some transmog gear so I decided to see what I could do.
Solo'd all off TOC on 10 man, (jaraxxuss on 25man), very easily zerging them down, except Jaraxxuss (25) which I died the first time because I ignored the adds, second time I killed the adds as they spawned and he went down easily enough, took some time tho.
In Ulduar, FL, Ignis, XT, Big statue guy with arms, crazy cat lady, and Mimron were all easy enough, mimron I did at 85 as well tho so w/e.
Naxx I mean to do KT 25 man but I forgot to change it cause im stupid but yeah KT and saph (10 man) were zerged. Instructer Raz (25 man) was easy once you AOE'd down the adds, Gothic the harvester (25) and 4 horsemen (25) where easy.
All off this was as Enc.
Honestly, I wasn't expecting it to be this easy. I'll be trying KT and saph 25man on reset, and some ICC to see how it goes. On the bright side i got all off the pieces off transmog gear I wanted (barring the KT weapons since I had it on 10 man instead by accident).
Trolls are out of the question for now. ...Didn't try ZG[COLOR="red"]
I'm not so much after the challenge of soloing, but after the ZG panther. And as elemental I managed to take her (he/it) down: I keep myself topped in the first phase, I don't bother with the adds, kick the spell of which the name escapes me now (not the shadow bolt, the other one). and right before phase 2 starts, lust / stormlash / ascendance/ fire ele / pot and spam lava burst. It's a very close call and I usually die from the panthers at the moment I kill her. Tried the normal way by killing the panthers one by one, but it takes longer and it's easier to screw up.