Okay I don't know if Apple fixed something or what, but I just downloaded new 110 MB episodes of my podcast and they finished in about 60 seconds or so, chugging along at 3+ MB per sec or 24 Mbps, which is the download performance I'm seeing on my home wifi with this phone using Speedtest.
What actually happened was I opened the podcasts app, there were 2 new ep's which started automatically, but I paused them both for a few seconds to check the dates and ep numbers on them. Then I manually started the latest episode which zipped down in about 1 minute. Then I started last week's episode, and it was CRAWLING! It only got maybe 8-10 MB down in 2 minutes. I paused it, started it again and BOOM! Done in under a minute!
I'm thankful that its finally downloading this stuff with decent speed, but I still wonder why the massive speed difference just by pausing the download and starting it again?