HTC builds their phones so the processor passes it's heat to copper tape, which transfers the heat directly to the metal back. This is intentional and does a great job of keeping the SOC cooler than other designs, but it can cause concern for some users that are not used to feeling the heat being shed through the back that way. If you have GSam battery monitor, it will tell you the actual internal temperature, which will be about 80 to 85 degrees F sitting on a desk, and up to 113 degrees in hard use like gaming or updates.
The sunglass issue depends on your sunglasses. Some of the better ones (like genuine Ray-Ban) are polarized slightly diagonal (left one way, right the other way). My $400 prescription sunglasses are fine as well. Now, I'm NOT saying that sunglasses that are polarized flat instead of having an angle are cheap, and I don't have a list of ones that are or are not. Just stating my very limited experience. Your mileage may vary