Both feel that DotA should remain a "community-owned product that modders, independent developers and game fans can continue to modify and play as often as they'd like," explained in a statement to Joystiq.
Mescan thinks Valve's move is an attempt to exercise "control over its future." He feels the "DotA name should remain the property of the community at-large, as it always has." The current developer of DotA-Allstars, IceFrog, has been maintaining the project since Feak left. He was hired by Valve late last year and it appears that his team will release a version of DotA through Valve.
Feak and Mescan's comments make a few assumptions about Valve's intentions for DotA. For all we know, it will be a free game that ships with a full SDK like the recently released Alien Swarm. It could go the other way and be a regular, paid release. Valve has not made any announcement yet, but Gamescom is this week and might be a great place for an announcement.