I'm not a fan of increasing DPI to increase icon/window/font sizes, unless you have a large monitor. That being said, trying to run 120DPI on a 1024x600 (or worse 576) is probably going to frustrate anyone. I just tried 120DPI on my wife's Mini and I don't see any "blurring". I understand the windows being bigger, but that's to be expected.
As for the wireless card problems, it's been my experience that some wireless cards do not play well (or as well) as others with wireless access points due to inconsistencies with coding. I had nothing but problems with my Netgear access point when I got my Mini 9. I replaced it with another brand and now it works great.