What I wish was different
I wish my time had been a bit more structured, especially in my second term. When I got there, I don't think anyone really knew what I would be doing (I was the first co-op they'd had in manufacturing in a long time). I was given tasks that were fairly simple, and mostly things the engineers meant to do for a while, but hadn't gotten around to. I transitioned to a different part of the manufacturing department when I signed on for the summer, and my project was a lot more open-ended. I was mostly trying solutions to the problem, gathering data about what worked or didn't. I don't feel like I made much progress there.
Another thing - I was mostly working on my own projects independently, which is valuable, but I would have liked to work more closely with another engineers, or even the other co-ops. As the only co-op/intern in the manufacturing department (the rest were in R&D or elsewhere), I didn't get to know my fellow students as well as I would have liked.
Finally, there was a lot of stress all around the company, especially in the first few months I was there. I came to understand that there had been talk of layoffs, which eventually happened, and everyone was on edge for that whole time period. The way the higher-ups handled the situation hurt the company's image in my mind.