This is the deck I play, and the hardest match for me with it is mage burn. It's too much direct damage to deal with. If you can apply that philosophy to other decks it may work, but I think they lack the hard removal (poly) and 15+ direct damage.
In general I find Hunter a reasonable match-up, mid-range or aggro. I guess I would say it's important to use your removal wisely, and make sure to get as much value from Deadly Shot ect. as possible.
I don't play Rogue or Warrior, so I may not be much help assessing those decks. Rogue can't, I don't think, keep pace with Warlock across the game, so it's important to use bursts to finish them off when needed. Assassinate would be useful in this match, and silence is always very important. Avoid playing lots of smaller minions as they'll just be wiped away by Hellfire or Shadow Flame. I can see why Warlock Giants is a hard match for this deck.
For midrange Warrior, silence is very important. Most Handlock decks play many threats (4 giants + Alex, 2 Twilight Drakes, and sometimes something else like Rag or Sylvanas). This means you need to be very careful with your limited removal, so silencing the Drakes then using a weapon is pretty ideal. Make sure you're playing your large threats in smart ways: they'll always Siphon Soul some big/scary stuff, so try and keep key threats back. Don't over commit, as double Hellfire is a legit play. Try to keep some burst damage for them, and going for a kill when their around 12 - 15 is best. Use Execute to push damage through past big taunts.
Sorry if nothing I said was any help, but this is the best I've got. I play Giants because I love the deck and it's solid, and other than Mage, I don't find it weak to anything. Good luck, and I really hope you can beat it with the decks you like.