I've been to the Tales of Graces answers section and it is believed that, in this game at the least, Accuracy increase the staggering effect of your attacks, and Evade reduces the staggering from the enemies' attacks.
Do you think it does the same in Tales of Eternia ?
Yes, but in Eternia there's not a lot of ways to increase/decrease your accuracy, the main difference is daggers have higher than normal accuracy and big sized weapons have less (although it's not a HUGE difference).
Accuracy buffs/debuffs do make a noticable difference, however one thing I noticed (but didn't really test) is enemies cannot evade while staggered, so once you start a combo and chain a bunch of spells with other characters, accuracy becomes more or less useful.
But for particular 1v1 fights, accuracy is REALLY important.
Grand Marshal/Gladiator Priest, Lightplol. PvE gladiator holy paladin, Lightp.