You will cry. At least, that's what I did. In the two and half years I've been an assistant professor I've cried more than in all of graduate school, which itself was a rather grueling six years filled with setbacks. [But high school and college, overall, were quite pleasant for me.] Rather than give you a list of pros and cons of being in the academy, I'm going to try to talk you out of it as much as I can. If you've come to read something like this to see if you should be a professor or not, let me make it simple for you: If you have that much doubt, don't be one. And if you don't, then one blog post isn't going to stand in your way anyway.
Being a professor puts you in an awkward position of power. After years of irrelevance as a graduate student, you have a voice that matters. You get to decide your own syllabus, you get to decide if you use a curve and, yes, you get to decide if that student working at less than their potential deserves a C or an F. I was uncomfortable with that sort of power. The first F I gave tore me up. I had to consult with two other faculty members who told me, "yes, definitely this person should get an F." We like to plot students on histograms. Whoever ends up hanging out on the left margin too much? Fails. Those histograms form blobs; when there are gaps between blobs, we separate them out into "A", "B", and "C"... It's a random, arbitrary process sometimes. But so is life in the many other ways we evaluate people.
But giving an F is nothing like the worst thing I've done. Having to fire a student isn't anything I wish upon anyone looking to motivate growing minds. Another part of the power of being a professor is having money, and money can make all of the difference to a spouse in a refuge family. A research assistantship with stipend and tuition is one of the things you are expected to give out. If you're not a good manager, or you just hired the wrong person, you'll have to terminate the assistantship that doesn't work. You can tell yourself that you are giving them a valuable lesson, or that it's really out of your hands. But at the end of the day, you were the one who flipped the switch.
You can make a difference in your department. Even if you come from a superstar school with a superstar advisor, the odds are that your academic position is going to be at a "growing" or an "up-and-coming" department. That means your department will have plenty of flaws, many of which can be fixable if you just put in the effort. It sounds great that you can grow and leave your mark on the department, but when you come up for tenure, all of your "service" will amount to a single sentence of additional contributions. You also will be unable to avoid political aspects in your service, as reasonable colleagues will disagree with your approach, meaning that your "making a difference" will piss some people off. Don't keep your head down completely, but never try to get emotionally involved in the outcome of anything, no matter how clear it is to you that it's "better."
Academic freedom is for the few. It depends upon your department and the courses you're teaching [introductory, core curricula, electives...], but if you're not at a department that hands you a deck of slides and says "this is what you'll be teaching" you'll have a fair degree of freedom in the approach you take with your course. Making the syllabus match your ideal course is a great feeling, until you find out that, well, your ideal plan has some holes in it. The more experience you have with it, the more you end up conforming to the "tried and true" formulas. Depending on your personality, this might affect your enthusiasm for teaching. I'm a software engineer, so I believe working on a software "project" is essential to really learn how to program. But I know another software engineer at a different department who was told "you can't do a project in that course, because they already do a project in this other course..."
But what about research? Sure, you have academic freedom there too. The academy studies what is important, and academic freedom means the academy itself gets to decide what is worthy of study. You can have a new take on a sub-sub-discipline. People might say "wow, that's an interesting idea!" But unless you convince enough people that your idea is worthy of study, it's not going to get published, and it's not going to get funded.
So, the next grant you write? It's not what you really want to work on, but rather a mix of what is currently hot (i.e., funded, like green projects, or security) and what is safe (i.e., incremental improvements to the state-of-the-art).
You will be told that you need to be an independent researcher. But that does not mean now is the time for you to save the world. All that it means to be an independent researcher is that you publish and get funded only with other junior researchers (and your students). Stay away from working with people more senior than you, and in particular stop working with your advisor. If there are things you still want to publish with someone more senior, be sure it accounts for only 20% of your CV or less. Even if it was all your idea, the more senior person will get most of the credit.
When you start, the only thing you'll be qualified to do research on is incremental improvements to your dissertation. This is a nice route to take, because you can publish with only a few months of work [instead of spending six months learning a new area] and the more you continue your dissertation work, the clearer it will be to others that you've taken ownership of it. I got really interesting in end-user programming when I started my appointment. I really wish I could get those six months back in exchange for a few minimal deltas of publishing units.
[At this point, the dear reader may think that I'm actually giving you advice, or that perhaps I'm doing a Swiftian spoof. No, but I'll concede that sometimes the truth sure sounds like a joke.]
Do you get the academic freedom after tenure? Maybe. You'll still need to fund students, and that means you'll still need to get past the guards at the funding agencies. I do basic research in software engineering, and the funding opportunities for me is quite limited. So much concentration into a small pool can lead to groupthink.
Your peers include the anti-social, and actual sociopaths. Forget about discouraging replies from reviewers who "don't get" your submissions. Imagine creating policy and voting on issues with these people. There are sociopaths in the academy. Some of them act quite charming. They'll kindly agree to write letters of recommendation to eager students, only to throw them under the bus with a damning "recommendation." Instead of insisting on "no," they gladly take it upon themselves to let the world know how much so-and-so really sucks. They will repeat this pattern when you are coming up for tenure. When your case is discussed, there will be a pro side and a con side. Be sure you do enough good work for the "pro" side to have strong material to support your case. Don't bother trying to win over the "con" side. They will smile sweetly to you while burning your case as much as they can, even if their argument relies upon making a damning case against another faculty member coming up for tenure at the same time. [That's known as collateral damage in war.]
Students will manipulate you and disappoint you. Finally, let's talk a little about students. Yes, you are very clever, with that sob story that you constructed six weeks in advance. You really pulled a fast one over on us, didn't you? Well, no, not really. We are almost 97% sure that your bullshitting us, but that nagging 3% and just the hassle of it all means that you'll get away with it anyway.
As for the less clever, thanks for making it easier on us giving you a bad grade. If you do poorly the whole semester and only find religion at the end of it, no amount of earnestness is going to make doing "an extra credit project" [i.e., more work for us to grade] attractive.
Now, what about the students who don't fabricate stories of illness and dead relatives? Well, some students you will really like, and really root for. They'll impress you so much early on, that you'll start to talk to them about considering graduate school, or, if they are already in graduate school, working on a research project with you next semester. But working with students can kind of be like starting a relationship: Sometimes it's your fantasy of the perfect student that is blinding you to the reality of the actual student. Once that reality comes crashing in, you'll find you've invested a lot of time in someone who won't give back even a quarter of what you've put in.
So, given all of these, does the academy need changing? No. You just need to accept that sometimes your dream job is still a job, and hope that the great moments outweigh the bad ones. Until you understand what a really good day feels like, you won't be able to put all of the rest of this baggage in perspective.