In terms of how they aged, once Innocence was old, I could just hop into a blind party and 1 shot Innocence with them throughout Shadowbringers, even if the new person kept dying to the bait mechanic.

With Titania, it took until nearly the end of the expansion before most of the mechanics could be safely ignored by most of the party, with the worst obviously being the tether aoe mechanic. Once I could just say I'll take all of them, every single one, that was quite a big help. Sometimes I didn't intend to take all of them but their confusion led to me doing just that.