I'd actually take the other side of that argument. Vb.Net for the most part forces old hierarchical and event-driven programmers into a purely object-oriented paradigm that actually encourages the writing of poor object methods. Your old VB 6 teams probably aren't trained in writing class drivers, for instance.
So those teams are going to be writing classes that get introduced into production code without first being fully exercised in your pre-production environment...simply because they don't know (how) to test all of their class properties and methods.
"Object Oriented" doesn't magically obliterate spaghetti code, after all. If you don't exercise your pre-production classes with professional class drivers, then your new object oriented software project is going to be more kludgy than whatever it was that your team was writing prior to their jump into OO.
There's truth in that... people who are used to writing spaghetti code will write more of it after they learn how to define a class. But I think one of the issues on the table here is whether Microsoft made a conscious decision to leave some of the dumber ones behind when moving to .NET. If you've ever put an ad in the paper for a VB programmer, you know what kind of crap is out there. There are former shoe salesmen with IQ's of 55 writing VB. The scientists probably have a chimp that can do it.