I understand that taking away the random order makes it slower but still like the idea of torrents because of the big amount of available clients / implementations already available. 
Was wondering how YouTube etc do the random seek as they don't have do download the whole file for that either, maybe it would be possible to do something similar with torrents, idk. You know the file size, and length of the video from headers, so you could tell the torrent client to download from byte X which should be around minute Y of the video.
I'm not very knowledgeable about torrents in detail, so thanks for the input.