FFTA still has the exact smae problem FFT did. You only have a vague idea whether or not any jdispatch mission is going to be completed sucessfully. If you pick a character who is jumping up and down for the mission they're about 95% or 99% likely to succeed. However there is still the occasional chance of failuer, at which point it seems you can never try the job again.
I was doing a clan battle (which are usually pretty easy) while wandering around waiting for a mission to be finished. Unfortunatly i forgot which element was forbidden and which was encouraged, and one of my mages got a red card :( (which is strange, cause he didn't have any cards before)
I turned the game off in frustration, and now i need to redo the setup for the dispatch missions i had done =P
I had been planning on using only the one save slot, but i'm thinking it would be easier to have two stages of saves going. That'll make things difficult if i ever decide to replay the game again though.