I don't trust Wizards to be very consumer friendly with their VTT considering I think Paizo's complete openness of rules and options minus fluff is significantly more friendly to everyone. Mind, Paizo is the exception compared to every other company, but I hope that they would set a standard now.
I wouuld also be somewhat weary in terms of the system requirements for their VTT considering the use of Unreal. It can scale down but I wonder if they will have any difficulty in reaching a market that other VTTs do not.
Finally, the fact the VTT is specifically for D&D means it's going to not get the revenue streams of others or allow pivoting, which a sizable percentage of customers likely would want. And I know D&D is nearly the entire RPG market, but it's still a flaw.
This is semi-offtopic but I will note that Fantasy Grounds only changed to Unity in the past few years. No idea why they changed too Unity in particular, but I'm guessing it was purely for easy of development and they did not invest a lot in performance.
Hussar, I am guessing you have tried other options than Fantasy Grounds? It seems like quite an expensive option commpared to current competitors, but I presume there's reasons you've had to stick by it.