Lot's of you people really don't understand luck and variance whatsoever. First of all, most of you in a low bracket are NOT skilled enough to leave the bracket. You simply are 1500 players and need to improve your gameplay before you try to move up. For now, I'll give you guys that are complaining about being stuck in the 1500s the benefit of the doubt and assume you actually are a 1700+ skilled player.
In this case, you need to understand that HoN by it's very nature is game where luck plays a huge factor. Don't get me wrong, it's a skill game by all means, but it is heavily influenced by chance. Rune spawns, RNG of spells, etc. all play a part in determining whether you win or lose certain games in the short-term. If you are a player that solo queues, the luck factor is accentuated immensely. Not only are your short term results influenced by the inherently variant nature of HoN, but also by the teammates / opponents you get. Are your teammates having a bad day and throwing on purpose? Is one of your teammates someone who was boosted and actually plays like a 1200 player? Is someone on the enemy team a smurf? Or, perhaps one of your teammates is a smurf and the enemy has a really bad player whose throwing, giving you a huge edge to win the game? In the end, you have to realize that you won't ever get close to 100% winrate even if you are much better than your average player in the games you play. Hell, even as a VERY skilled player whose way above the MMR you play in, you still will have trouble getting 70%. The good news in that if you consistently play well, don't get aggravated, don't start flame wars, don't throw to spite teammates, and don't make any other emotionally-induced decision likely to hurt your chances of winning a particular game, you WILL climb in MMR until you reach the bracket you deserve to be in.
In short, you have to unerstand there's lots of luck involved in being a solo queue HoN player, and that even if you get 500 gpm in a game and dominate mid, it does NOT mean you are entitled to win the game 100% of the time. You will lose games where you dominate, and you'll sometimes win games where you feed. It's all very volatile, so don't get all upset and self righteous when you lose a game you were doing well in. It's part of the experience. If you want to always win when you're more skilled than your opponents, go play chess where there is basically zero variance. As long as you play HoN you have to accept the swings. If you consistently get 500 gpm and dominate mid, I guarantee you you will move up. Over a long enough term the luck factor evens out, so your true skill will be rewarded.