Necron's Grand Cross moved not three but FOUR planets and included a FIFTH one... Neo Exdeath's Grand Cross sent the universe into peril...

Time Compression may be a nice thing to pull of, but in the end it's effects are not harming. Everything is gone, so none can suffer from it's effects. Bit different like, when Kefka terorizes the planet for a year, or Kuja setting the whole surface of Terra on fire. Or even Sephiroth's meteor could have been devasting if it had landed.

Time compression? Seemed to go painlessly for everybody to me. And again, what did Ultimecia gain with it? Prisoned with immortality as the sole living being in a nothingness. At least Neo Exdeath wanted to die together with the world... I guess I shouldn't ask for the results of destroy-all-attitude. Especially when it it's obtained for once, even if only for one, weak form that's only able to do 2 attacks... Of which one can never be deadly. Nothingness doesn't make sense when it's not executed by a pop-out-of-nowhere boss. Unless Ultimecia was insane, of course.

EDIT: Now that I think of it, not many FF Final-Bosses make good sense. =/