There’s quite a bit of coverage of Perry‘s holding with respect to the initiative process.  A smattering:

In California:
LA Times: Prop. 8 ruling raises fears about effects on other initiatives
Orange County Register (editorial): Prop. 8 ruling blow to direct democracy
Sacramento Bee: Supreme Court gay marriage ruling raises questions for California initiative process
SF Chronicle: Some supporters of Prop. 8 ruling leery of impact on initiatives
      and here: Did Jerry Brown, Kamala Harris “refuse to do their jobs”?
San Jose Mercury-News: Marriage ruling raises ballot measure questions
Long Beach Press-Telegram: Attorney: California ballot measure system may be weaker after Prop. 8 ruling

and beyond:
Governing: What the Supreme Court’s Prop. 8 Ruling Means for Voter-Approved Laws
Kevin Drum in Mother Jones: The Big Problem With the Supreme Court’s Prop. 8 Decision
Allysia Finley in the Wall St. Journal: Democrats’ Prop. 8 Veto
Scott Shackford in Reason: How Concerned Should Ballot Initiative Lovers Be About the Prop. 8 Punt?
Joshua Spivak in The Week: How the Supreme Court Crippled Direct Democracy
Tamara Tabo in Above the Law: What’s Horrible About Hollingsworth Is Horrible for Us All  (yes, Above the Law)
Paul Waldman in The American Prospect: Why the Prop. 8 Decision Should Make Liberals Uneasy