My first post! Yay!
According to a few PTR testers (via this MMO-Champion thread : http://www.mmo-champion.com/threads/122 ... y-soloable
), both Viscidous and Razorgore (the two main "un-soloable" bosses) are being toned down in their mechanics to make them more solo-friendly.
While some classes still may struggle on Viscidous, there are some end-arounds for a couple of caster classes.
Casters with no frost damage : use a wand that does Frost damage OR use a low level weapon enchanted with Deathfrost and a Frost Oil.
Melee with no frost damage : Same as casters (excluding the wand, of course).
Casters with no true melee capability : This one I found to be a bit more interesting. While the thread doesn't cover this strategy (though I may have pointed it out in a post in there, I forget exactly), this is what you can do.
-Equip a fast attack speed 1-handed weapon (a dagger will likely be your best bet)
-Summon any pet(s) that can do melee attacks
-Use two trinkets that summon melee additions (Barov Peasant Caller, if you obtained this before the Scholomance revamp, is ideal)
A death knight without haste boosts using a two-handed weapon and popping Army can break the Shatter. This should be more than sufficient to do the same. If not, only one additional person should be required.
To highlight the Razorgore change, his health has been increased and his Egg Smash ability now has a 1.5 second cooldown. This makes this encounter vastly easier to solo.
The only questionable encounter is (if he drops a pet) C'thun, which can be soloed (albeit taking an incredibly long time to do so) if you pull Ouro (the giant worm boss) before engaging C'thun. This allows you to be "pulled out" of the inside of C'thun when you get transported in. This is the only mechanic that, currently, can kill you on this encounter, as the inside of C'thun does percentage health damage and not a set amount (even 80's and 85's could die in there if not quick enough).
The three bosses in Naxx in question are 100% soloable, and most bosses in between can be skipped. The spider boss cannot web the person with primary aggro, Gluth in 10-man can easily be DPSed down (you will likely need to either save him for last or commit suicide to get out of his room, however...Thaddius is not soloable), and the same applies to the fungus boss.
I hope this helps everyone!