About Arrow: it's a very tricky card. it does nothing for SMN and it drains TP from MNK and NIN instead of helping them. The best DPS to receive it are BLM, DRG, BRD and MCH. Those last three will prolly require a Spire later on if you use too many Arrows on them, but they won't run out of TP like MNKs or NINs do; this is because those two jobs already have speed buffs from GL and Huton. Expanding the card dilutes it's potency and makes the Arrow much like the Selene buff. It's also good for healers during some healing checks, but it can drain MP as well. Since it's tricky, you can use it for RR without losing too much. It's not surprising that the two most tricky cards (Spear/Arrow) give us the buff to double the next card we use; I think the change SE made to those RR effects (they used to give us the AoE effect before) were on point, since the double duration effect is too valuable and burning an Ewer or a Spire is out of the question during raids.