These days I use past tense as much as I use present tense. I used to think past tense looked /really/ odd when I came to Balmung, and how exactly I changed, I'm not sure. Future tense I use sometimes when I am following up on an action in the same emote, usually happens during combat or similar situations where explaining what your character would do with a lead up move is going to be too confusing in a new emote some 4-5 minutes later (since fights can be at a slower pace). The would comes in as me presenting how it would be if the action succeeds, I suppose to give the other player something more to work with, especially if the lead up looks really weird. It can also be a way to communicate to the other player that everything you do is interrupt-able, and you would acknowledge the interrupt because there's no possible situation where they'd dodge it. That's my take on it anyways.
ETA: Forces of habit can be really strong as well, sometimes they just don't make sense.
ETA: Forces of habit can be really strong as well, sometimes they just don't make sense.