According to PC Gamer:
"[on buying Valve] We hope to make better games, that will appeal more to our audience, and make Steam more kid-friendly, by removing social features, and limiting the ESRB for only Ec-T ratings. Also, with the purchase of Valve, we will have a better team to develop our games, such as the upcoming "Shake it Up: Interactive Dance Studio", and "Phineas and Ferb: Summertime fun". We also asked Disney whether or not they will continue creating original Valve games "Well, even though Half-Life 3 is planned for a 2017 release, we decided to scrap the game, and start it from scratch with a less violent atmosphere, and a planned ESRB rating of E10+. One of the big changes we are gonna do to upcoming Valve games is more product placement, and classic Disney characters you can interact with in game". When asked about Gabe Newell's standing in the decision, Disney CEO,Bob Iger, responded "Gabe Newell agreed to sell Valve to us if we agree to continue Valve's series Left 4 Dead and Half Life. He wants to stay in Valve, but we are negotiating with him so he could leave, and we could put our own Jerry Smith in charge of Valve."
According to them it will be finalized in August 1st and Disney will be fully in charge by September 2013!