Yes it does suck.  Sucks badly in fact.  But Paul, why does it suck?

Once you enter the final dungeon, the game cancels out pretty much every command except for attack.  You can’t save, use items, resurrect dead party members, draw or summon GF’s.  And you have to fight a string of about eight bosses.  After you defeat a boss you get to choose one option that had been cancelled out at the start of the dungeon.  So I chose GF so I could spam Cactaur.  I love that little green dude and he does 4,000 damage and arrives really quickly.

But Quistis died during the next battle.  I can’t use a Phoenix Down to bring her back, I can’t cast Life as magic is out and I can’t go back to a recent save as I haven’t been able to save in the castle.  Without her, I died in the next boss battle so I had to start over at the beginning of the castle.

So I fight the first boss all over again not letting Quistis die this time.  I’d really like to be able to save but I also want to use Draw and all the other options.  But if I chose to recover the Save ability then I’m sorta gimping myself for the next battle as I can’t cast Magic or Draw new magic or use items or…  You get the idea.

It sucks badly.  It basically guarantees that you have to repeat the dungeon several times, re-fighting the same bosses over again and hoping you haven’t chosen your skill setup poorly.  If so, you’ll be starting all over with the dungeon again.