Well, in the pre-gem version, it would be ok to remove most restraints, since a working version is set in the lock file anyway.  We could just get rid of all of them that we know we don't need, run bundle update, and then add them back whenever we're sure we need them.

With the gem, however, there is no lock file, just a range specification, and you definitely want constraints there.  Otherwise the bundle will install properly with obsolete packages.  Given that, it makes more sense to me to keep the constraints there.