Could the Transmutation Circle in Xerxes be reused even if it wasn't partially destroyed? I understand that Transmutation Arrays, the circle on Mustang's gloves, etc. are capable of being reused. But does the same physics stand for a large scale transmutation circle used for sinister acts? And also, what about the Nationwide Transmutation Circle in Amestris?
While not explicitly declared, we have every reason to assume that transmutation circles are reusable...assuming a few things. I base this off of observations of all of the (as you called them) transmutation arrays that we see tattooed onto people or stitched onto their clothing, or carved into their metal equipment. I'm further connecting it to the fact that there is apparently not anything too special about these 'permanent' circles, as
Mustang carved one onto the back of his hand and was able to use it just fine.
So, here are the assumptions.
1: Your transmutation circle is not destroyed when the surface it is marked on changes. For example, in the original anime, Ed gets himself out of trouble by scratching a circle into a set of restraints. When the restraints change into something else, the circle is destroyed because he morphed the material it was marked on. Or any of the times Al uses a circle to launch chunks of Earth at enemies.
2: Your circle is marked in a way that is not easily disrupted. A lot of the temporary transmutation circles we see, such as the ones that Al uses, are drawn with chalk. Chalk smudges easily, and the transmutation reaction may be enough to smudge it. And, as we have seen, transmutation circles need to be very precise in order to function properly...so a bit of smudging should be enough to ruin it. Another way this could be messed up is if a liquid is spilled on the chalk...like the mess made at the end of Ed and Al's very, very failed human transmutation attempt.
I can't find an example of this actually happening with a 'drawn' circle, because Ed and Al have a tendency to use Alchemy that destroys their transmutation circle...and the times that they haven't (see: repairing the radio in Lior) they only intended to use that circle once. However, in that case, the circle remains intact and appears to be completely unchanged...so I see no reason it couldn't be used a second time.
Furthermore, in the 2003 anime, we see transmutation rooms set up that have the circles painted onto multiple walls. If the circles only worked once then had to be repainted...there'd be no sense in using paint in the first place...chalk is much cheaper and quicker to work with.
All told, there isn't any reason to think that transmutation circles are somehow less re-usable because you didn't stitch them onto the back of your glove or engrave them onto a gauntlet. As long as you don't mess up the circle, we have every reason to believe that they could be re-used.
In the case of the Xerxes circle or the Nationwide Transmutation Circle...we have every reason to believe that they could have been re-activated, assuming the two things I stated before are true. Naturally, I assume this means that one of the first things that they set about doing after the final battle was damaging the array so it wouldn't work any more.