Might as well at least mention this year's revelation, which is that they fund fake Grassroots campaigns against tax reform: http://www.propublica.org/article/turbotax-maker-linked-to-g...
And time management is notoriously hard. Not to mention this will need security up the bum.
How much would it cost just to read all the documentation and have the program certified, so it can do what it's supposed to do without writers getting sued?
I believe that if it were to actually do the e-filing, the people who ran the e-filing would have to submit to federal background and clearance checks at those people's expense and the servers it ran on would have to probably get FISMA High certification, provided it actually posted to the Efiling API.
That's just my speculation, fwiw. But I think that's true.
Filing taxes correctly while maximizing benefits is incredibly difficult. There are tons of ambiguous rules and loopholes and fuzzy boundaries and it changes all the time.