The shakespeare generator isn't just reproducing the syntactic structures, it occasionally seems to capture meter. The samples you've reproduced here aren't iambic, but they are around ten or eleven syllables per line, which is impressive enough in itself. In the longer passages, it manages some proper iambic pentameter:

   My power to give thee but so much as hell:
   Some service in the noble bondman here

It doesn't seem to have managed to pick up on rhyming couplets, though.

A quick search of Shakespeare's corpus also shows that Shakespeare never called a bondman 'noble'; there must be some conception of parts of speech being captured by the RNN, to enable it to decide that 'bondman' is a reasonable word to follow 'noble'.

So yes, "unreasonable" seems about right.