Thomas Shey
Legend
As a former software developer I believe that a D&D "aware" VTT could be developed with out copyright issue since one could implement the rules as a mechanical thing.
That is the rules engine in the VTT could be instructed to manage all the dice rolls needed to play D&D.
What get into trouble is the additional modules that automate character creation (as @Enrahim2 states above)
I do wonder that if the VTT did not provide such additional assets but say a rich die roll macro language and a tagging system to identify text boxes so that a user could recreate a character sheet and automate the die rolls to the chat log (or what ever) would that count as fair use on the users part or would the user be exposed to copywrite claims by WoTC.
Personal feeling on that is that its going to be really hard to Hasbro to sue them for, essentially, the digital equivelent of what anyone who puts together a fillable PDF character sheet and tools thereof can, especially if its set up so it applies to a variety of game systems (not that that's easy to do in a way that's actually easy for an end user who isn't familiar with layout to use; I've seen several attempts in various programs and bounced off them hard, and I'm probably better skilled in related areas than the routine user).