Would be cool if they added a hardcore version of Ambuscade, where you do 5 waves of random ambuscade battlefields one after the other (kind of like SR). You get the same points as a VH clear but the amounts chain, so wave 1 is normal reward, wave 2 is 25% more and on till you beat them all and the final one gives double reward.
If you clear the whole thing in time a treasure box spawns and you get 50-100 job points (for rema upgrades?) and a chance at some recolor of those light saber weapons or something.
Limit of once per day.
That sounds pretty impossible unless you increase the time significantly. The fastest VD runs ever go are 5 minutes or so, but those are with setups that are geared specifically for that that one and often involve SPs, and that's only possible for some of the Ambus.
Ambuscades are very setup dependent to clear quickly; what happens if you have a Bard and a COR, and suddenly you get the Qiqirn Ambu and it takes 15 minutes because you had to wait until songs and rolls wore before you started? What if you get the mage Mamool Ambu and you have no one that can supertank or AoE sleep? Bringing versatile jobs only goes so far when you have to clear each one so quickly.