I think the best thing to do is contact Google and make them aware of the issue.
There is a contact form on the google play site
Its also worth checking that there's not a bug in your app that stops it from opening in certain phones/devices (which may or may not be your fault, could be firmware issues). But you'll generally see users select 1 star rather than writing reviews. Remember users are lazy :)
As @64BitsPerMinute suggested in his comment, there may be some frameworks that could help detect crashes. Have a look at ACRA, or for a more managed service have a look at HockeyKit with the HockeyApp plugin. These services allow you to get crash + stack reports from your users when thins go wrong. Even if the users don't report it back to you they can click one button and send instant crash results.