The community features of Wuala are great, but instead of downloading FLVs from locations like youtube and making local copies of them, then uploading them to Wuala... there should be a more simple mechanism to show others youtube/etc videos!

A few options for integration:
a) a FLV extraction & upload system into Wuala. This requires a lot of extra coding and results in more space used over the network mesh... The only upside to this is that videos cannot be removed by Youtube later on due to ToS issues.
b) An "add via url" feature for linking to youtube... Dbl click on the icon and your default browser opens it. Simplest and "just works". As a developer the "downside" is that you're pushing people out of the Wuala framework, but it shouldn't really be considered an issue because Wuala is almost like a file browser and isn't normally the center of attention once a goal is achieved. I like this option best, and you can use it for linking to things that aren't youtube + comment on it in standard Wuala fashion :)
c) A more complex version of B, have an integrated flv player inside Wuala that plays files from external urls... yuck. Feature creep much?