A disabled plugin MUST NOT be loaded!

[mvlcek]

Unfortunately the system as it is must read each file to get the plugin information, name etc...

Yes, I agree, thus a plugin is initially enabled.
But as the plugin rules say that the plugin name is the same as its filename there is no need to read it again, once it is disabled.

You can cache the plugin information in an XML.
Or - I suppose - you can read all plugins when displaying the plugin list, it shouldn't do any harm. But don't load the plugins at any other time.