I think the main weakness of that idea is that any enemy contact will cause your fleet to launch all the drones it can. This means you need supply ships with no launchers to maintain a supply past the first battle (or the first turn if on the defensive).
However you can get them all to attack at once. They'll work that way in simultaneous movement mode if they all have the same speed and aren't trying to get through a warp point.
I think in sequential-movement mode, you can also get a volley attack by selecting several drones and giving them an order, the same way you do for Groups of ships you want to move together without a fleet.
PvK