Does turning off features modules affect what the features modules does?
FWIW I've successfully uninstalled modules required by a feature before, but I had to remove the dependency from the feature's info file first and then disabled and removed the module. I've seen several Features where the creator unwittingly auto-added all sorts of modules and dependencies to the feature, so just because a module is listed as a dependency doesn't necessarily mean that it is really needed. As this tutorial points out, we should "Build natural dependencies, prevent arbitrary dependencies." and it's so true because as these arbitrary dependencies creep in, a site's features become more difficult to manage.