The problem with your suggestion is that the order of plugins matters and you often want the newest at the bottom (since it may change the behavior of plugins that are loaded earlier).

I agree on the tick/untick box for enable/disable. I make a lot of test installs and it is quite annoying to have to go through that process each time. You could submit the idea to Elgg's trac as a feature enhancement.

You might have seen my version of the PlugIns Listing --http://community.elgg.org/pg/pages/view/19473/ -- I did this to basically sort by different columns, filter by olugion grouping, author name, etc... not to enroach upon the official Commuity PlugIn listings ;-)  -- just wanted to have more info available to make it easier for 'searching' for PlugIns.

Regarding the 'PlugIn' to handle what is described above -- I suppose that refers to the Admin of Tools ? I dod have a look at how Elgg stores this on the database -- then with the intent to export the appropriate DB rows - do some smart editing, sorting of the data (grouping) then import back to the DB -- but that would have been a "hack" -- I might spend some time (late nights) reading over the core code to see what might be involved in order to do such a PlugIn to manage to manage plugins/ tools ;-)

The plugins can already specify dependencies. They are just not acted on yet by the core.