How do I update Boot Camp w8x64 rMBP

When I first bought this computer, 13" retina, Boot Camp 5 wasn't available. I installed windows 8 on it. Now, I'm wondering what are the benefits of updating boot camp. The mouse trackpad is really agrivating me to the point of wanting to sell this computer. I don't want to because I'll miss its lovely screen. I use trackpad++ and it helps, overwhelmingly, but it isn't enough. Also the sensitivity is crazy on this machine. I don't even have to physically touch it and it triggers. [Just in case the climate affects it I'm in Florida.] Sometimes when resting my fingers on the homerow the bottom of my thumb triggers a response from the trackpad.

I also have hi-DPI problems.

A lot of times with checkboxes.

These are my settings, which also display another problem I'm having. In the Custom sizing options window, the font is very bold. It's annoying.

Another common HiDPI problem is the buttons cropping text. Also very bold.

Again buttons cropped this time in height instead of width. For both Server and connections

Typical weirdness that happen with certain applications.

These problems are NOT with all applications, especially Microsoft.

It may have to do with the text scaling settings because I see similar problems when I connect to an external monitor.

I know I got a bit off topic, but it stems to the root of how to install bootcamp 5 and it's pros/cons. Also I'm open to suggestions on problems I'm having with my rMBP. I'm thinking about moving to a Lenovo Helix if problems persist. I have a x201 tablet that has a way better keyboard, but I can't use it anymore. The screen ***** compared to the retina.

Thanks in advanced.