You should still be worried. Just because googlebot expensively evaluates JS for some websites doesn't mean it will evaluate JS for your brand-new website. You might get crawled a lot less deeply than if you had good content in your static pages.
By abandoning their AJAX crawling scheme as described in the OP, they are essentially saying that they will evaluate JS for all sites. Do you have some reason to doubt that?
If crawling with JS costs 1,000X or 10,000X as much as crawling without, it's fair to say that even Google isn't going to crawl 100s of billions of pages executing JS.
As a former web-scale search engine CTO, my opinions are commonly surprising to folks who haven't built a web-scale crawler/search engine.
My own experiments/experience shows that recrawls happen about 1/3 as often and tend to lag a few days behind for JS content vs inlined/delivered content. It's helped a little by dynamically delivering the sitemap data, but even that only speeds things up a little.
My guess is they're putting about 1/10th the effort into keeping things freshly indexed for JS, but may well be devoting 2x the resources vs directly received content.
About a year ago I wrote a post[1] about how I couldn't get google to index my AngularJS app. My main problem was the interaction between googlebot and the S3 server. I'll have to go back and test if the crawler's behavior will render the correct content.
I have the .html5Mode set to true so it was routing based on push state.
I hadn't gotten around to creating a process to generate the sitemap.xml before I gave up on the site. For SEO, we were more concerned with getting the time sensitive content indexed.
We recently built a site for a customer in Ember and their SEO guys were concerned about indexing. I wasn't sure how it was going to work out, but in the end Google has been able to index every page no problem.
Do you know if they sent Google a sitemap? Our client is insisting on a sitemap that has pointers to every-single-product. Something on the order of 2MM+ product pages. It seems like a bit much to me
> Break up large sitemaps into a smaller sitemaps to prevent your server from being overloaded if Google requests your sitemap frequently. A sitemap file can't contain more than 50,000 URLs and must be no larger than 50 MB uncompressed.
The site is built on Tumblr which automatically generates a sitemap for the individual posts, but not any other pages on the site. For example the "about" page is not in the sitemap, but is still indexed.