Full disclosure, I'm a CPA.
Most simple forms could be filled out by people, they simply are intimidated and/or lazy.
To those calling for the IRS to do the returns, however, I think you are entirely misinformed as to the competence of the IRS, state and local governments.
If you would see the errors and notices they make on a consistent basis, you would not want them calculating your refund or the amount you owe. Uninformed taxpayers are often willing to pay the notices simply because of their fear of the IRS. If the IRS were in charge, I don't think these people would be well served.
For example, in the last month I've seen a $500.59 1099 turned into a $50,590.00 by the IRS, a widow sent a notice for stock sold where basis was excluded from the calculation, and a state tax return where the state returned the check and then sent a notice for funds due. These agencies are undermanned/incompetent or both in many cases.
Before you brand me as being self serving, most of my clients are high income/high net worth who wouldn't be impacted by your proposals. Based on my experience, however, you don't want what you are asking for.