So I've been reading the description of the vow arcanas and I'm trying to decide which one is the most broken. I've currently torn between earth and sky.
Earth: In PvP your enemy ends up killing himself no matter what. As soon as 3 to 4 of your own buddies die the other team is pretty much dead.
Sky: Pretty much infinite HP. If you have good support (Accolade, Ares, Shyvana) the only danger to you are instant kills. Pair up with maxed out True Hathor for lulz.
So far my money is on Earth for PvP (though maybe countered by Shyvana?) and Sky for PvE. My runners up would be Moon because seriously, screw rage reduction + stun.
For Vow Temptation I hope we will be getting new pictures, i.e. not the ones from the storyline. I also hope that they are affordable and not the 20k gold recharge insanity we get for costumes. Also a download option would be nice...
Edit: Nevermind, you get the necessary items from daily missions. The screenshot suggest 4 Master Emblems to open the fourth piece. If we thus assume the n-th piece needs n emblems, that's 171 in total or just over 17 days to unlock one picture, assuming double gains from daily missions and no boosts through events.
You seem to receive around 25 vow points on avarage per Servant Emblem, so if you go to 350 mission points each day, that's around 1k vow points from 42 emblems. Level one needs 1k, level 2 needs 2k; if this goes on it's 36k to 9, or just over a month.
Edit: The screenshot shows 5k for level 5, so I guess that's confirmed. This also means that by the time you unlock level 9 for Vow Temptation you probably have enough Master Emblems to unlock every tile.
Edit: More detailed numbers below.