I'm feeling a bit stifled in my city and want to move. My priorities are $1500-2000/mo rent and a path to an affordable house (see: picture), a unionised city workforce, good greenspace with an extensive parks system, good biking infrastructure, a good public university, and a good political scene. That leaves Portland, Minneapolis, Chicago, and maybe an East Coast city I haven't researched yet. Of those, Portland is at the top of my list because I'm getting an ocean for Great Lakes prices.
What's bad about the city that makes people move away? Is there a better option in Oregon, especially one that would let me commute into Portland without whatever problems it has?
Portland's nice but a few things: It's on the Willamette river, 2 hours from the coast. And the coast of Oregon is pretty mountainy and stormy. It rains a lot in Portland, so seasonal depression can hit everyone for like half the year. If you don't already have a job, there isn't much industry in Portland proper aside from healthcare, government and higher ed. The neighboring cities have some options like Intel and Nike. Oh also the state has a super racist history, used to be a whites-only state that confederates moved to after they lost the civil war. Portland proper and some of the neighboring areas there's a bit of diversity but outside that its pretty white and racist.
Outside of these things, it meets your other criteria
I used to live in the PNW and now live near the Arctic Circle in Scandanavia. I would absolutely kill for Portland sunshine.
SAD can be an issue but I always go somewhere sunny for at least one week in January (the heart of winter) to get some vitamin D. If OP has a good job going south in winter (especially to the desert) is a good option. Supplements can help with SAD as well.