I sure wouldn't, because I worked on the VB.NET compiler team back in 2008-2009, and "organizational overhead" was pretty much the whole game. The VB and C# compilers were completely separate codebases, managed by parallel but non-overlapping teams of engineers. We never touched the C# compiler's codebase, and the C# people never touched VB. (I did once read through a piece of the C# compiler source code, to see how they'd implemented a feature I was supposed to be reimplementing for VB, so I could be sure to use the same semantics: but that was it.)

We had lots of meetings, though. Oh, god, so many meetings. So much time burned keeping all those parallel projects in sync. Whatever commonality the languages have occurs through endless soul-crushing hours of almost-pointless meetings sorting out how these two separate pieces of software are both going to be modified to do pretty much the same thing, with almost exactly the same syntax. Every new feature had to be designed twice over, implemented twice over, tested twice over, and documented twice over. They may look like twin languages, but the illusion is maintained via massive, ongoing investment of sheer brute force man-hours.

Maybe things have changed since I was there, but it's really difficult to imagine how that could happen. The VB compiler was effectively legacy code, a horrible creaky mess of ancient patched-together bullshit, and nobody wanted to touch it any more than necessary for fear of breaking something. Refactoring was totally out of the question. I cannot imagine an organization as sclerotic as devdiv managing to rally the effort it would take to rewrite it - safely! - such that the VB and C# codebases could be combined far enough that they would no longer need to have a separate VB compiler team.