I'm a huge RvB/AH fan boi, and for me, a 30 min run time is nothing. They often have Let's Play!s that will run 30+ mins, a few have even crested the 1-hour mark. And I have watched every single one. They have shorter, Let's Do!s that run in the 10-20 mins range. So for me to sit down and watch other people play a game for 30 mins at a time ain't nothin', just so long as the video is edited well, the commentary and comedy is there, the time flies and you're entertained.
However, most people aren't like me and they don't have the time to sit and watch for that long. So perhaps a lil' bit shorter run time, so long as it doesn't feel compressed, may be more palpable for the majority.