StarCraft II: Heart of the Swarm's lead designer Dustin Browder recently said that company Blizzard Entertainment is "looking at" turning the multiplayer portion of StarCraft II into a free-to-play experience.
During a panel at the Valencia eSports Congress (via PCGamesn), Browder said that the main concern was to figure out the structure for updates if balancing changes were to be made. "We don't know how [Blizzard] would monetize it. While it might be good fun for me to play against someone with only half the units available to them, that's not going to be an enjoyable experience for them."
StarCraft II: Heart of the Swarm is the second part of the StarCraft II trilogy and is focused on major character Kerrigan and the Zerg species. No release date has been announced yet. For more information, check out GameSpot's recent coverage on the title.