I find the current system of just having hearts indicating that you like a video vs keeping track of videos restrictive. I want to keep tabs on videos to download, and since hearts are the only way to add videos to the collection, I heart videos for later, and when I download them, I un-heart them. This is unfair to the video creators when I do actually want to indicate my support, but I can't do so without clogging up my collection pages. And on the flip side, if I do keep a heart on videos I've downloaded, now I have to keep remembering whether I hearted that video because I liked it and/or because I haven't downloaded it yet.
I know there's the option to add videos to the watch later list or make a private playlist, too, but while that could function as a download list, it's not nearly as convenient, because it's not immediately visible when browsing when you've added a video to a playlist, so you have to click on each video's submenu to check whether it's on the list or not when browsing the general collection.
I'd suggest implementing a system like VirtualTaboo does, which I find more usable: have two separate markers, one for likes (hearts) and one for favorites (stars), both of which are visible and clickable while browsing. Favorite videos are added to your collection, while likes are purely for supporting the video. Separating out the functionality between the two allows us to indicate support while letting us manage our favorites however we wish. It wouldn't be too destructive to migrate the current SLR collection to this system either; treat the current hearts as both a like and a favorite to start when implementing the split, and it will behave the same as before.
Alternately, you could tweak the video browsing interface so that it has clickable "watch later" icon on the video similar to the heart that you can see directly from browsing and not have to go into a submenu to see/modify. Personally I think the idea of splitting up the collection and like functionality is more understandable, but adding such an icon would essentially allow similar functionality.
