First, thank you for writing. We don't know the results of some of the changes without feedback. We have noticed that the new player seems slower at first than the older version. After I used it for a while, I didn't have problems. I don't know if it uses cookies or what.
Here is the story on the speeds. We have found that the picture actually runs faster if it is shown in the original size. We make them 854x480. Rather than have a slower speed menu button, there is an icon on the player you can use to get a slower speed. In the bottom right next to the time stamp and the full screen arrow icon is a checkerboard. This allows you to pick a slower speed. Please try this and let me know if it works for you.
Oh, also remember that we have a player that will buffer for a short period of about 5 minutes. Start the show, then pause it. It will buffer in for about 5 minutes. Then when you start it up, the show has been read in for a little bit and the will run cleanly until it catches up with the buffer. The buffer will be a lighter yellow color.