No, this will be great if they can keep it as far away from WINE as possible.
You can *already* install WINE today, use it to install Steam and Windows games, and the vast majority work with very little hassle (I own dozens of Steam games that I play exclusively on Linux via WINE).
*This* will be better, because you won't have to suffer through any problems with bugs in the abstraction layer the next time Valve patches their game clients. Things will just work, without those occasional hiccups that only the hardcore can workaround.
There's absolutely no reason for WINE to be involved with this at all, and if it were it would put us back to right were we already are. WINE is a *great* project, and indispensable to most people switching to Linux - but its function should be to fill the gaps when a native solution isn't available - not to slow or dissuade native Linux development.
This could be the start of much better video driver support, and improvements all around for platform agnostic APIs.