Gratuitous cutscenes, annoying barks everywhere, huge useless animated portraits. It is basically the blizzard polish, looks better than it plays. Not that Starcraft plays bad, but none of the fluff contributes to gameplay. And that gameplay takes a lot more micromanagement than it needs to(some people like this. me, not so much).

None of that has anything to do with why starcraft is popular, though. Starcraft has a long history of organized professional competition, and that's responsible for sustaining interest in the game.

sound (and lack of it) is something that gives aa lot of balance to the game

in brood war you get info when units are made and sounds wben they die. unless an invisible dark templar one shots your units, then no sound

also brood war is the better game