While she's unquestionably brilliant (I may dislike her, but I'm not blind :) I really doubt she could fix something a Time Lord couldn't... so we could have heaps of fun with her insisting of mending it, thinking she's got it right... and finding out she hasn't when they end up on Planet Omigodwherearewenow????

Just about any of the Doctor's reaction to that would be even more fun :)

Alternately, one of the little souvenirs the Doctor picked up on his travels, somewhere in the bowels of the TARDIS, turns out to be a quantum mirror...