I'm a bit concerned about mapping clinics and doctor's offices as areas around property. They are not rendered by Mapnik, and I'll bet it won't be rendered anywhere else. My suggestion is to simply put the amenity tags on the buildings themselves only.

the off-ramps are connected from the Marquam Bridge upper deck (layer 3). I changed the layers from 2 to 3 for that reason. if the layer of the off ramps is 2, then the map will look like the off-ramp is under the Marquam Bridge, which is not true.

Putting destination names as name values on motorway links is inappropriate. You can use two methods: the exit_to key (which put exit sign details on the exit number node, more at exit_to=*) or the destination key (which puts exit sign info on the ramp itself, more info at destination=*). Make sure you use the last sign showing the street name/exit number on I-84, not the street blade at the end of the ramp.