that thread he link to in that tweet is really interesting:
there is a dll called 'clrhost.dll', which descript itself as 'For managed server in the Windows Runtime', its version string is "4.0.30319.16698 built by: NETFX4WIN8"
inside it are some strings start with "NetFx45_" which indicate some settings for .NET Framework 4.5.
I heard there are some hints about ASP.NET 4.5 inside the server build, so .NET 4.5 is comming.
there is also a string 'ARMEnabled'
reassuring, but this is still a PR nightmare