I think HTC's greatest strength, when they are applying it, is that they can make some high quality feeling devices that compare very favorably to Samsung's terribly cheap feeling light and shiny plastic junk when you pick them up and hold them in your hand.
If I were them, I would focus on that. Take some design risks like they have in the past, make some phones that are a little more daring, but sleek and masculine looking. Think Braun shavers.
Do that, and have at least two solid WP8 devices ready to do at launch and ACTUALLY ADVERTISE THEM.
It's OK if they are sold as Android devices too. As much as I hate that, it's a business reality and HTC probably isn't in a position to design unique phones for WP yet.
But this time, do it the other way around. Launch them as WP8 devices FIRST. The Android masses won't even be paying attention to WP anyway and probably aren't going to feel slighted by getting a phone design that came to WP a few months earlier. By putting WP8 first, they'll be doing something different, and that will get them some free media buzz.
Make two sleek, Braun shaver looking phones for WP8. Target businesspeople and more mature types moving away from Blackberry with one and give it a physical slide-out keyboard. Emphasize the MS Office etc.
The second model, make small and sleek and cheaper. Target it at young women who are educated. Emphasize the social media aspects of WP8, but that it's also a phone for serious people.