I rather likes the 2-hour abilities of FFXI.
In my opinion, I've always considered - in both XI and XIV - TP abilities to be the replacement of 'Limit Breaks' in the games, because they act in the way limit breaks worked in the rest of the series (and for people saying they're not iconic, they are; they're simply named differently in the various games).
But the 2-hour abilities were awesome, and I would definately support a revival of these in FFXIV.