I was about to post this exact same thing. AFAIK the only way to change the order currently is by removing and re-adding devices. There really should be a global setting for this in the Sync settings.
There should also be menu entries and hotkeys, like Container Tabs has.
I spend time putting tabs in an order, especially in tab groups. Then, after sending to a different device, I have to re-sort the tabs, since the order has changed. Shouldn't have to do that extra work.
Also, down the road, when tab groups can be sent to a device, people will expect the tab order to be identical on both devices.