Pretty much all of current homeworks and exams can be. It's called standarized tests, and I'd argue it's one of the reasons education sucks as much as it does.
Except from that one, where I think a move in opposite direction is desirable, I'd love for all the changes you mentioned to happen.
To be honest I don't think anything can be done to the 'education system' that will drastically improve the results. The bottleneck lies with the children (and their parents) and their thirst for knowledge (or lack thereof), which is a reflection of the culture and values they grow up with.
But what we can do is save a boatload of money on costs.
there's software that almost every higher ed university uses in their lower division courses to administer homework electronically. it grades the homework for the instructor and populates a gradebook. it's pretty hands off.
as far as I know, they have packages like this for every lower division STEM class. I used this software as late as multivariable calculus.
English homework can't be graded by computer, but subjects like math, physics, and chemistry could conceivably be checked by computer. There'd be some details to work out, such as how to "show work", but it could work.
It's just like using TAs, except with casting a much wider net, though a lot more details would need to be worked out.
Remember, you have the advantage that grading a paper is easier than writing one (in compsci terms, the former is in P, while the latter is NP-complete).
Questions are also probably better handled with an online (or offline) forum and office hours. At any rate, I was never overly convinced about the 'interactive' benefits of the lecture hall.