If I am in total agreement with the Petitioner's claim, then do I need to file a Response at all? I have read that it simply defaults and continues the dissolution process. I don't want to file a Response if I don't have to.
Recognize that your ex can do anything within the boundries of what the original complaint said. If she said she wanted a "fair and equitable" distribution of property, her idea of "fair & equitable" might involve her getting everything & you getting nothing. If he asked for joint custody of the kids with liberal parenting time and child support, his idea of joint custody might involve him being primary parent and liberal parenting time might involve you seeing the kids as long as you show up with gifts on thier birthdays & Christmas only.
Also, in some states (I'm not sure about California), it takes longer for a divorce to be finalized by default (just because the judges don't like not hearing the other side's position about whether this stuff really IS fair or not, and would like to give them every chance to respond.)
If you want a quick & easy divorce, file a formula response and ask the other party to bring you a copy of the decree. THAT will be the final thing that says what is REALLY happening in the divorce. AND if you agree with the decree, then sign THAT.
It's usually better and easier to have a consent decree than a default divorce. If you're on speaking terms with the ex, explain that you're going to want ot sign off on the decree and could they forward a copy to you, and you'll file the formula response just to make certain you get a chance to see & approve of the decree before it goes final.