In short: when i import my vimeo rss, no videos get embeded. just thumbnails.
Vimeo RSS exports an 'enclosed' swf. SimplePie automatically handles the enclosed video and embeds it. I tested the feed on the simplepie demo page.
WPeMatico does not pass along the 'enclosure' when importing the RSS to post. This causes the video to not have a chance to be embedded.
I'm digging into the WPeMatico files to try and find a solution.
Unrelated side not, WPeMatico isn't running the latest version of SimplePie.