You'd need about 126 speed from gear just to get an extra tick per minute. This wouldn't help SMN much at all, as an extra pittance of MP every minute would be underwhelming. Meanwhile, NIN and MNK would last much, much longer. MNK and NIN would basically have an extra Invigorate every two minutes (assuming Huton/Greased Lightning count). BLM might also wind up spending slightly less time in Umbral. Healers would also have a field day with it. Basically the group least benefited by it is probably SMN. >_>