I'll give that list a try.
Right now my biggest problem is that I'm simply getting overrun by the decks out there and I simply can't keep up. When I win, I win big but it seems like there are just too many games where I'm simply trying to hold off the inevitable.
Warlock: Zoo is all about how my mulligans are. If I get good early cards (fiery waraxe in particular), I don't have too many troubles with Zoo. But when I get hosed, I get hosed in a bad way. Handlock seems to be getting the correct removal at the correct times and keeping track of their threats. If I'm able to, effectively, deal with their giants, it's not too bad. If I can't, I'll lose.
Paladin: This is almost an auto-lose for me. Muster of Battle + Quatermaster is SO good that it's hard to keep clearing their board 3 or 4 times a game. They can just nickle and dime me to death and it's hard to outdamage them when they're running 30+ points of healing. Honestly I think Paladin is one of the strongest classes right now and I've had some hilarious wins with them. Turn 5 or 6 wins aren't uncommon with the Muster + Quartermaster combo. Even if 2 of the little shits get buffed, it's a hard board to deal with for a lot of classes.
Priest: I hate playing against Priest so I just auto-concede. This one is on me. I simply don't find it fun to have my own cards, constantly, turned against me. Since I'm not hitting Legend this season, there's no reason to put myself through 30 minutes of hell where, even if I win, it was a miserable experience. I like playing priest. I just hate playing against them.
Mage: Very similar to Zoo. Either I win hard with lots of early removal to transition me into the late game, or I'm overrun by mech after mech after mech.
Shaman: This one seems like another coin flip. I either have absolutely no problem beating them or they have perfect answers for everything I try to do.
Hunter: I'm favored in this one but it all comes down to having Fiery Waraxe in my opening hand to deal with their turn 1 Undertaker. With Hunter, it just bothers me how they will hard mulligan for Undertaker and it seems like they ALWAYS get him. I hard mulligan for Fiery Waraxe and it seems like I never get it. I know this is just a perception thing but it annoys the fuck out of me knowing what's coming and being helpless to do anything about it.