@grandia20Hm...that's a tough one. The ability is very strong to say the least, as it can be used in numerous ways. So perhaps some extra limitations? Like...they only speed up/slow down for X amount of real seconds, they can only manipulate one target at a time, and can only do it at a certain percent (like...they move 50 or 100% faster/slower).
I state these limitations bearing in mind that characters will grow over the course of time and their abilities will get stronger as the crew overcomes challenges. Such as extending the amount of time, the amount of targets, and being able to manipulate speed with more variety (like being able to range it from 10-100% as necessary for example) or perhaps even speeding up immaterial things, such as wind.
And yeah, we unfortunately have a doctor character already, but the Time-Time Fruit could certainly come in handy if they were a cook or even a navigator. In the case of the latter, they could speed up the ship for hasty getaways. If they're a navigator, they would be able to tell the best times when to speed up/slow down and where to point the ship ahead of time.
@jynmi88I think we have the basics of everything down. Usually, I prefer a PM as well, but it might be good to have a thread. The Characters tab will help us keep a record of the extra characters we inevitably make.
Eventually, we'll also all need to double up as we gain crew members...and we'll eventually need non-Devil's Fruit users as well. We'd probably want
somebody who can save a crewmate if they get shoved into the water. xP Though that doesn't need to happen now of course.