I love the Engrave platform, but as a constructive criticism, the inability to log into a blog directly is a huge problem, unless its just a temporary issue. If its a future design feature I'd suggest against it.
This means that for my company's posts to be rewarded with upvotes they have to go to Engrave first to sign up. Maybe you think that's good for exposure for Engrave, but this is a huge problem for bloggers. Huge enough for many to stick with wordpress.
I would change that as soon as you can. Because as much as I like Engrave, that's a deal breaker for me.
This is of course just a temporary issue. We're developing a brand new mechanism to login into blogs which will enable cross-blog authentication. It will be even more useful for your readers than before because when someone will log in once, he will be logged in to every blog on the Engrave platform. This is just because we totally changed the technical way to render blogs.
Logging directly on blogs is one of our most valuable features and it won't be abandoned, don't worry ;)