No, you still can't set Chrome to be the default browser in iOS. However, with the latest version of Google's browser, available in the iTunes App Store, you can get to the web a little quicker on your iPhone or iPad.
The browser can now appear as a widget in the pull-down iOS Notifications Center, for example. Adding the widget will show two Chrome options, one for a new tab and one to perform a voice search. Since the Notification Center is always available with a quick swipe down from any screen in iOS, this feature can get you browsing in practically no time.
This also lets you use Google Voice Search instead of Siri in the same time it would take to activate Apple's voice assistant.
Personally, I like this approach. I find that between Google Now and using Chrome on all of my other devices, I get a more cohesive set of personalized results with voice searches. Siri has improved over time but is still lacking when it comes to providing as much contextual information.
Chrome now has a pull-to-refresh gesture, making it faster to get the latest information from the web in the mobile browser. The gesture can also be used to open a new tab or close the current tap by moving left or right when pulling the page down.
Google is also taking advantage of the app extension system Apple added with iOS 8. If you use a password manager such as 1Password or LastPass -- I'm a fan and long-time user of the former -- Chrome for iOS will work with it. That means you can have your passwords in Chrome automatically filled in on a form or website as the browser will work directly with a pre-installed password manager.
With these changes, it's clear that Google is still trying to make Chrome as attractive as possible to iOS device owners. There's only so much it can do, however. Apple still requires Safari to be the default browser and I doubt that's going to change any time soon, if ever.