I'd like to make a suggestion regarding cursor size. Right now, the game's resolution affects only how it's rasterized, and this is a good thing because it prevents players with large monitors from gaining an advantage by using a large monitor. All resolutions display the same square area of map in the view, and the UI takes up the same proportion of on-screen space. This is fantastic. However, there is one exception: the cursor.
The mouse cursor, not being part of the game space, does appear to be dependent on the way the game's resolution. Its size appears to be a fixed to something like 32x32, but it's 32x32 contextual with the resolution of the game client, not the resolution of the screen: this means that at something like 640x480, the cursor takes up a whopping 5% of the screen's width, whereas at a massive 2560x1600 it takes up only 1.6%, and is comparatively microscopic.
For me, this is a problem because I have a very hard time following the cursor at high resolutions during large engagements because of this. There's a lot of action going on, and if the cursor is the size of a zergling it's easy to get lost. Because of this, I play at the lowest widescreen resolution possible, because for a game it's function over form pretty much always.
As a smaller point, I would love to use SC2 as a chat client and more of a social platform by simply staying logged in so that friends can message me to play. However, because I play on low resolution it takes a long time to change desktop resolutions when I Alt-Tab in/out of the client. Thus, I log in only when I want to play, and log out when I'm done, and the people I've met in the game and the people in my channels simply can't reach me.
For pros, the opposite situation could be a problem, too. Lots of pros/serious players use low settings to crank better FPS out of their machines, and since resolution has a significant effect on FPS it's possible that this is one of the settings that are lowered. It's quite possible that hey have no problem following the cursor, but when going to low resolution it goes full duplo-mode, which they might not like.
I'd like to suggest a setting either in Graphics or Gameplay that is a simple slider (stepped or continuous) that adjusts the size of the cursor in a way that's more dependent on screen resolution that it is client display resolution. This way, players can play at the resolution they want with the cursor size they want. Thanks!