By the end of the 17th century, which European nations were in better shape, and which were weaker, than they were at the beginning of the 1500's?

Your use of the term "17th Century" means the 1600's,  so
your question spans the years from 1500 to 1699.   By 1699 the English, French, and the
Dutch were quickly gaining on the Spanish and Portugeuse in wealth and in world
dominance.   Since Spain and Portugal were still quite powerful nations in 1699,  its
really hard to pin down exactly which countries were dominate.   By the late 1700's
however;  with the British in firm control of much of India,  the Americas (minus the US
of course),  the Caribbean,  and other parts of Asia,  I would conclusively say they
were the most powerful nation at that time.  Spain was on the way out,  with most of
their new world colonies soon to gain Independence.   But in 1699,  world dominance was
very much up for grabs.   But Spain and Portugal were clearly losing influence world
wide mainly to the British, French, and the Dutch.