Aaron-
Fantasic paper.  Yes, a SWOT analysis would be in order, and as you said, the key is to set goals.  For example, it has been my experience that when volunteering for Gospel for Asia, it is best to get an idea of how many books to pass out and names to collect in order to "break even" for the cost of the booth for the event, then add a significant amount to that for the return on investment.  On average if a ministry like GFA gets $15 on average per donation, measured by one name and address, then we divide the cost of the booth by 15 and see how many names and address would be needed to break even, and then add an amount so the gain is realized.
Just see the Clover festival posts on TF recently and you will see that not everyone will be happy and you obviously cannot please everyone, but if investors are paid pack plus a little extra, also taking into account the exposure of their brand/organization, then they will invest again.
Measurable results are the determining factor of deciding "was this worthwile"?  We are called as Christians to be good stewards of our time and money, and basically setting goals and measuring results are the way to determine the answer to this question.  Everything else falls in the realm of council of a large group of advisors.

Communications is most likely the vehicle for promotion on any level, and this is marketing in a nutshell.  In this day and age, if you can google it and/or watch it, you will most likely consider it worthwile.  So make a YouTube of last year's XFest footage and get it to as many people as possible to see, or make one this year for next year. Oh, and contact Scion to have a large ad in the festival program, which will most likely pay for the program, and maybe get them to "sponsor" (pay for) a stage with an Artist that has 1 kajiliion friends on myspace

Thanks again for the info, and I encourage everyone playing at, promoting, organizing, and/or attending any festival this season to read the material that Aaron provided. Thanks bro, hope to see more of this from you.  You ought to hit up Dave R to possibly publish this on TF magazine?