There definitely are valid concerns with this approach...but until the search engines pick up the slack, this is the solution that we're left with. It's definitely not ideal, but I prefer it over having non-DRY code just to serve incomplete HTML to crawlers.
The alternative solution is pushstate with an acceptance that you will need to either do some duplication of effort on the server side rendering or creating something along the lines of the AirBnb Rendr framework. I am in the process of doing the former with the plan to do the latter with a future iteration.
