As someone who used Visual Basic 1.0 for DOS through Visual Basic 4 (VB5 did not run well on my i80486), I wonder if there is a lot of value in being so compatible with VB6 at this point ? Admittedly I have been out of the VB scene for a while but I assume all the VB6 code that exists doesn't justify this.
Other projects that promise a Visual Basic like RAD experience might be better, such as GAMBAS [0] and vTcl [1].
[0] http://gambas.sourceforge.net/en/main.html
[1] http://vtcl.sourceforge.net/