It kind of depends on what type of blog you have of course - if you're hosting a blog of opinions that are a little longer that what you'd write on Twitter, then sure, Google+ is all you need.
Otherwise you need control.
Did you know for instance that Wordpress.com does not allow advertising of any kind without profit sharing with them? And many of us don't expect any profits from our blog, but it is sure nice to throw an Amazon link to a book that you'd really like to recommend anyway, and get a month worth of hosting back.
And sure, Google+ is not Wordpress.com, but IMHO they are worse as their primary business is not hosting blogs. Even if the product is new it already has a history of blocked accounts (WTF is that all about?). If Google blocks you, your identity is gone.
This is not how the web should work. You can host your blog in GitHub pages, static content is all you ever need. You're a developer, so you don't need a stupid WYSIWYG interface that never works as you expect it to. You can write Markdown or Textile or plain HTML and keep it in a Git repository.
For comments you can just use Facebook or Disqus, or implement your own quick and dirty solution in PHP or something cheap for starters, like GAE or Heroku. Well, Heroku is not cheap, but you can host 250MB worth of comments in CouchDB for free by installing an add-on.
Personally I have my own $20 Linode. I host there 2 blogs and a personal app I'm working on. Nginx is a very light process, it's easy to setup and can withstand an HN-effect on only a small instance. It's also good enough for a Wordpress install if I wanted that, but I just don't bother with Wordpress.
Don't host your blog content on third-party providers. Get your own domain, host static content for free or pay for a small instance - make sure you can rebuild that blog if banned from the service provider - and only submit the links to Google+ or Facebook or whatever, otherwise you'll later regret it.