Let's talk about Sharpcast.

[Sleigh]

Well I never use swiftcast to actually open a fight, that's what precasting is for. But wouldn't it be a DPS loss to sharpcast Fire 1 and then open with F3 instead of just hard casting F3 and following up with Fire 1? The latter is nearly a 50 increase in potency versus sharpcasting F1 > Firestarter. It only takes you about .46 seconds more of total time to get that 50 increase in potency which I find to be worth it. But I guess if you're anticipating casting interruptions, it could be useful.

MP mainly. F3 is expensive, F1 is not. To see what I mean, try a raw F3 into an Enochian rotation vs a raw F1 into an Enochian rotation, without using Convert (as you wouldn't have after most phase shifts). The F3 is also a very good way to insert non-GCDs instead of doing them raw.