I wouldn't be in the mountains without some sort of rain gear. You probably won't die if you're caught in the rain without it but it won't be a comfortable time. Some consider sparing it until the High Sierra and even then I think it's not a very good idea (you still go through really high ground in SoCal and it can get ugly) but until Washington? There are some better ways of saving weight than going without. I'd get at least a Propore jacket, it's just 5 oz.
The Driclime may be nice but it's not rain gear. And I don't think a wind *vs.* rain jacket is a good way to put it, they're different things with different functions and both have their place. Actually a very good strategy is carrying a very lightweight rain top to use only when it actually rains so you don't have to cope with the limited breathability too often and use a windshirt the rest of the time (which on the PCT may be most of the time).
The PCT, as any long trip, is more a mental issue than anything else. You can probably hike it all with no rain gear and you can probably hike it in a set of pajamas if you're determined enough. You can help your mental strengh by carrying a gear set that works (i.e. functionally, weight wise or even aesthetically if that matters) or press it harder by going without and still make it. I won't say it can't be done but I'll say feeling prepared helps keeping your motivation up.