User blog comment:BlazingKey/The Honest Truth of the X1 "Trial"/@comment-27948655-20150223230537/@comment-24463567-20150228222219

InferandGrahdensINC. I have feeling you're being ignorant of the difficulty of getting the Overdrive bar full, necessary for UBB activation. Sure there's the item to fill it instantly but you need to worry about both offense and defense (Quick correction here, the Angel Idols that Ivris's [Not Ivirisu] UBB give only are applied to 2 random units, so it could be your best ones or your worse ones). The Overdrive bar also increases with each use making it much more difficult to get in short and long quests alike.

To get Grahdens six star you need to do a very very hard quest (might be raid like, not sure) to obtain a certian material to evolve him. So you can't necessarily say that because he's released, it doesn't means the unit that the new units overshadow are completely and utterly useless

Who says that everyones going to have the units? The more units the better. More alternatives and possiblities for team compositions.