Yeah, traffic is bad. BUT.....you don't have to sit in it. I use the WES Train almost every day and avoid the daily traffic jams. Many other folks can use the MAX Light Rail. It isn't mandatory to use a car here. You can also bike - plenty of bike lanes and one of friendliest cities in the nation for bikers.
Homelessness is a huge problem, one that our current mayor has failed massively to address. Slowly, there are affordable housing options coming, but this problem was allowed to manifest for far too long and it's an eyesore. However, I don't think Seattle or San Francisco or other cities on the west coast are faring any better. This is a national problem and not one relegated to Portland.
Rain? Please. This is the best weather in the country and I'll fight anybody who says otherwise. Rarely above 100 degrees, rarely below freezing but we complain about a little rain? I LOVE THE RAIN. Keeps things green year round. I like the vibrant colors of vegetation given to us by the rainfall. You want brown frown? Move to Colorado.
Housing prices are higher than they used to be, but I'm not sure you're going to find affordable housing in San Diego, LA, The Bay Area or Seattle....not sure why Portland is getting singled out. As a homeowner for 20 years, I'm quite pleased with the results, but I'm weird. I like making money.