Definitely don't pick it if the first two are a problem.
Don't bother controlling the dragon.
Individual limitations and details would be up to the author/god, and you'd have to work around them as the user. All we know for sure is it takes blood and it eventually fades from reality.
The more limitations though, I think makes it more interesting. As long as it isn't completely useless. All you have to do is find the things that aren't limited.
I read a book a long time ago where someone could read books(picture books?) and the things inside would come alive and follow their desires. I don't remember how it ended, though.
There was also a light novel I read where the user could cast spells using single words, and as they got stronger they could add more words to make more complex spells. It was a kinda boring story though.
Writing a single word is kinda boring, and it doesn't fully take advantage of your talent as a poet. Instead, to maximize your talent, it actually makes sense to do something like this:
It's possible to make things with single words, but they're incredibly weak and simple. A full sentence will slightly increase the power, and the precision of the translation from your imagination to reality. But the true strength is when you make a full poem. A short poem, with rhymes, echoes, and other linked words, could result in something like an intermediate or even advanced magic. A long poem, ballad, or epic could have world altering power, as long as it carries the weight to move anyone and everything that hears it.
For my example, 'Dragon' may just summon a dragon made of ink that can make a single attack. No city destruction there. But if you read the Fate of Beowulf out... Maybe that might destroy a kingdom.