[quote=@Bai Suzhen]
It does seem like it still might be very open ended, and solve problems in a way that just makes for a boring RP.

Like... you might find yourself asking the question 'Why doesn't he just do XXX'? Like right now I can think of... transmute something into a new, unsunken boat, take that boat out to the marine ship and transmute it into sugar, make himself an impenetrable shield in combat etc.

I'd suggest including at the very least a size limitation (I.e. can only turn a pebble into something pebble sized), and that it only produces things he can picture in his mind, and so if he tries to make something too big, too complicated, or is just distracted then it's going to come out warped or broken.

Either that or go full Full Metal Alchemist and have it work on equivalent exchange.
[/quote]

[b]Power can only be used on non-sentient things.[/b] This limitation also applies to the users own body.
The wood the boat would be made of was living once and here is where the second limitation applies:
User cannot create life from nothing nor revive the dead.

As for the size thing, [i]Furthermore, dependent on the skill the user holds with the power varies the speed with which the user can change objects as well as the volume, mass and size of the changed object.[/i] As of right now, I would put his skill at around beginner to medium since he has some experience but not with anything too complicated.

[i] and that it only produces things he can picture in his mind, and so if he tries to make something too big, too complicated, or is just distracted then it's going to come out warped or broken.[/i]

Well, if its for complicated machinery, ofc he will have to be able to understand how the thing works or obtain a blueprint of some sort. and again, as time passes and he becomes more proficient, the size of things he will be able to change gets bigger and bigger. Right now, ofc he won't be able to change a rock boulder into a usable ship, firstly because he can't create wood nor understands how the inner workings of a ship are, to be able to picture them in his head.