It basically came out a few years before SC2, being even less graphically demanding. (At which point my own PC with a GeForce 4 which, for comparison to today, had either 0.064 or 0.128 Go of VRAM, would struggle to run it.) Some graphic improvements have happened since then of course, and the requirements are now somewhat higher.
Now the issue is that it doesn't have the unit caps that SC2 does, and the number of players (now up to 16vs16 in a normal game, sometimes even 32vs32, while in 2009 8vs8 would have been the max), map sizes, and number of units (typically up to ~0.5k in 2006 compared to topping up at ~5k-10k today) only kept growing.
So if you want to play big team games, and have a much worse CPU than the average player, you might not have the best time in the endgame.
I will first start versus AI, then take it from there. Not really a competitive player anymore. Playing Brood War kinda makes you dislike multiplayer RTS after a while, haha.
Now the issue is that it doesn't have the unit caps that SC2 does, and the number of players (now up to 16vs16 in a normal game, sometimes even 32vs32, while in 2009 8vs8 would have been the max), map sizes, and number of units (typically up to ~0.5k in 2006 compared to topping up at ~5k-10k today) only kept growing.
So if you want to play big team games, and have a much worse CPU than the average player, you might not have the best time in the endgame.