I like the second approach better, but ultimately, I would like greater fray flexibility. I'm an MMA fan and in that sport there's a saying, "styles makes fights", or better put, styles makes interesting fights. What if we could put a Chaos Legion team against an Alpha/Beta team? There could be an additional points award for using teams made up of earlier editions.
This would allow for guilds made up completely of new players to compete against established guilds. It would also allow for easier recruitment because you wouldn't necessarily be limited to the confines of the particular restrictions an open fray. The points bonus would provide an incentive to buy older additions as well. And it would also expose new players to the older cards as they would meet them in battle.
To be clear, I guess what I'm thinking is the frays being open to all cards but with limits on card levels and gold/regular foil, and with additional brawl points being awarded for using cards from older editions. The older the editions the more points awarded.