I think for most apps the chance of hitted by a BUG in 4.0/4.0.3 but fixed with 4.5 is quite low, very low I guess. on the other hand, 4.5 has few important new features so you wont miss it much, this is different than VC++ because C++11 is huge.

But if .NET developers had complained about this like VC++ users did, MAYBE ms could change this.