1) Good for Valve. I think this is the beginning of an already awesome company evolving even further.
2) Jeri Ellsworth (fired valve employee) was right. Some of the older Valve employees really have been holding the company back in terms of culture and new hires. This seems to be Valve's response by fixing itself and focusing on recruiting new younger staff. The problem with being an awesome place to work is that employees don't leave even when they should. They might in turn refuse to let younger employees in out of fear that they'll be replaced. So slowly it destroys the natural cycle of replacement of old ideas with fresh new ones. It might not be set up as a recruitment platform but it sure can be used like one to Valve's advantage. They can support kids who want to get into the industry and at the same time snap up the best of the best before other companies do.
3) Also, Valve hires only the most experienced who can self manage themselves. This has allowed them to do a lot with only 300 or so people but expanding seems to be slow. Other companies hire juniors, work them hard, pay them below market wages, and can expand faster and create more IP. If Valve wants to launch more IP or expand they're going to have to change their ways. And it seems they've come to terms with that.