Every HTC phone I've ever owned has had poor battery life. Most of them have been android phones, starting with the G1, as well a couple of that used a Windows OS. Part of the problem is that HTC chooses to use smaller capacity batteries than what would be ideal for their phones.
If you compare and equivalent Motorola phone to an HTC, Motorola tends to use bigger batteries in their phones.
The problems with battery life on HTC phones will not improve, because the company chooses not to build into their phones, better batteries to begin with.