If all you wanted to do is
increase the size of Blizzards Minimap, you could find an addon to do that. I know
Sqeenix does this. I know because I used to use it, but, decided to combine the maps instead. I know that it is out-of-date, but, the last time I tried it (a couple of months ago.....) it still worked. Tekkub's addons are pretty good that way. Maybe you can go back to "regular" resolution that way.