I will add some of my podcast thoughts to your post in hopes it will get some attention.
There are a couple issues with podcasts that i have brought up before.
In MC settings there is an area called "Audio (CD Rips and Podcasts)". It has nothing to do with podcasts. This section should have podcasts removed from it because the podcast directory is set in the Podcast section.
Another issue is if the podcast directory doesn't exist, all podcast downloads will fail. A warning saying the directory doesn't exist would be very beneficial.
TONS of double episodes appear in my feeds
I have noticed this with some of my feeds. I attributed it to the feed changing, but really don't know why it does it. I can confirm it happens though.
Move the podcasts to their own JRiver section (asides from Audio, Video, TV & Streaming). Frankly they don't belong to streaming and nesting them there make them unpractical to reach!
I like them where they are now. It makes sense because you stream them. If you download the podcasts you can make your own custom view wherever you want.
When I updated to MC26 I had to re add all my podcast feeds. I haven't checked to see if they are included in the library backup when updating to 27. Support for OPML files would solve this. An OPML file holds RSS subscription information and most podcast apps support the import/export of them. It would be a great feature to be added in to MC.
I have more small suggestions but will save those for another day. Overall MC does a great job of handling podcasts.