In terms of opera, there are things that I look for, but again, do not always need to be present in order for me to call something opera.
Let me offer, then, a few ideas of what I believe opera does not need to be:
Long.
Big (in physical size and resources).
Sung all the way through.
Set to an orchestral score.
Performed on a stage.
Live.
So, right away, as I "don't" define opera, there are already five or so awesome areas for growth/change. Think of any standard opera (and any standard opera company), and most likely you will find that almost all of these categories still fit the old definitions of opera. So, if you want to make a new opera, still in the tradition of opera, a good place to start is with these ideas: making opera shorter, smaller, include spoken dialogue, score the music for smaller instrumentation and electronic instrumentation, perform the opera outside or in a barn or in a dance studio or at an art gallery, or create an opera specifically for the medium of film (i.e. Matthew Barney's "Cremaster V", or R. Kelly's "Trapped in the Closet").
...However, in its place, I would like to count as necessary to art making those things that guilt proposes to negate; rest, sustenance (culinary, intellectual, spiritual), space, time, comfort, ease, attention, health, conversation, movement, freedom (from "should", from over analysis, to change one's mind ((multiple times, if necessary)), to let something brew, to be fiercely obsessive or to be unconcerned), and, perhaps the first thing that vaporizes when the call of guilt sounds its menacing horn: Pleasure....
This last week we had Ryan Tracy and Chris Schavio from Collective Opera Company here for a Creative Residency to work on their upcoming Scarlet Fever. Ryan blogged about their residency on the new COC blog, check it out...