Make convoy missions unavailable for two hours after abort/fail.

-1

Yes, absolutely.

If you kill an entire escort mission's convoy, it says "Completed".

I've "completed" an awful lot of convoys. I'd rather it do the MEGAKILL!, ULTRAKILL! MOOOONNNNSSTTTTTEEERRRR KILL KILL KILL, etc. progression as you drop the various ships.

+1, but
instead of 2h, make it progressive. Like 30', 1h, 2h, 4h...
If you fail/cancel, interval increase. When complete, it reduces.
And make delay to be faction-wide.

+1 for abort.

I'm not convinced applying it to failed would be an improvement. What circumstances create the failed state if losing all results in a completed?

No, if you get booted out of the mission for killing your own voy, it counts as completed. Sorry, I didn't make that very clear.

Autoabort if more than 49% of convoy is destroyed.
This will make convoying traders watch better for their ships!

instead of 2h, make it progressive. Like 30', 1h, 2h, 4h...

+1, btw