Rather than the only option being right clicking, it would be good to have an alternative way to give fleets move orders.
I suggest dragging the fleet to its destination.
While a fleet is selected in the fleets window, clicking and dragging that fleet's icon on the map, or that fleet's box from the fleet window, over a system icon on the map, then releasing, would give that fleet a move order to that system, if possible.
This lets the player select the (small) icon for a system's fleets once, then drag the larger, easier to click fleet boxes from the fleets window in order to give all ships in the system move orders, all with clicks of the same button, rather than the alternating left-to-select-fleet and right-to-order-move system now, which is more difficult to do quickly.
If we later show each turn's progress for a fleet along its move path while that fleet is selected, the player could instead grab one of the markers indicating the fleet's future position along its route, and drag that to another new destination. If we have queued move orders, this would give the fleet queued move orders, that would have it go to the route step the player grabbed, and then change its route to go to the new destination.
Additionally, rather than having the single fleet button always represent all the fleets in a system (or one each for those stationary and those not ordered to move), after clicking and holding a fleet button, a list of fleets represented by that button could pop up from the button. While still holding left, the player could slide up and release the button over the specific fleet s/he wanted to select. This avoids having to move the cursor over to the fleets window to select the specific fleet wanted. Alternatively, the list could pop up if the player mouses over the fleet icon, without needing to left-click it. The pop up list could show an icon and fleet name for each co-located fleet, to allow selection based on name and icon appearance (suggesting distinctive icons be made). Once a fleet is hold-selected, it would become the new default top fleet if the fleet icon is clicked, so that the player can click-select a fleet, then drag the fleet icon to another system, to give move orders to multiple fleets without having to go over to the fleets window.