I personally think this plugin would be a VERY helpful tool for server owners, especially those that are in a large clan with an insane number of servers in their arsenal. Take me for example:
Our clan is a large CZ clan (50+ members). We have a total of 12 dedicated servers of varied sizes owned and operated by myself and two other clan leaders. The three of us are CONSTANTLY coming up with new ideas for server mods to add when we get a new server or to replace ones that start to get less and less average traffic.
With this plugin, testing new ideas almost in realtime is possible because as long as you are using a plugin's default cvars (or editing the defaults in the sma before compiling to custom tailor them to your needs) you can stay connected to the dedicated server with your client, minimize the game for a quick moment to FTP upload the plugin file to your plugins directory, go back to the game, give the server a quick map change and voila!!!, you are already testing the new plugin to see if does what you need it to do for the mod you are creating.
I do wonder though if it could be possible to have it parse the plugins from a separate folder than the amxmodx/plugins directory.. or maybe from a sub of that directory? This would certainly be a nice feature to have because I personally like to keep a large collection of old and new plugins in my servers' plugins folders... and I might not want every ONE of those active at once. With a subdirectory, I could just drag and drop two and from that folder quickly, especially if I had a lot of plugins that I wanted to test individually or in small combinations.