If I may touch upon a point referenced beforehand I was curious as to the number of current Starcraft players vs. Starcraft 2 players so I did a little digging and I came up with these:
Starcraft 2: 3,669,507
Europe: 1,113,475
Americas: 1,316,282
Korea / Taiwan: 769,903
China: 322,343
Southeast Asia: 147,504
I couldn't come up with with concrete numbers for 1 but evidence seems to indicate it would be around same as it seems a lot of SK progamers etc etc. are sticking with it.
Unfortunately Singleplayer has not been the primary bread and butter for Blizzard in a long time. The popularity of games such as Diablo etc were driven by their Multiplayer and after the gigantic hacking shitstorms(Which atleast in the case of Diablo 2 stemmed from the offline portion) that occurred sometime after singleplayer interest faded in several of their games and sad as it is Blizzard sought to safeguard their primary interest at the expense of SP playability in new games to avert this because as mentioned prior multiplayer tends to be the driving force. There isn't much of a point going beyond that at this point because I seriously doubt anyones mind will be changed coming into this as people who play do so while those who don't simply don't and as numbers indicate that Blizzard won't be running into serious trouble soon so discussion at this point is picking nits etc. Truth be told solely focusing on the SP of this game would prolly be a waste until a GoTY release as the campaign is pretty meh.