Santana is always awesome!
In the industry it is called a "cover" when an artist plays another artist's music.
Often the reinterpretation is only barely recognizable compared to the original. "All Along The Watchtower" is an example that Jimi Hendrix "covered" from a Bob Dylan effort. Came out completely different.
Another example, "Pretty Woman" by Roy Orbison is almost a completely different song from the way Van Halen interpretted the work.
If you look at how Van Halen made the video, it would never have aired in these times. It was banned from MTV in the '80s due to the lack of taste.
There was even a parody done of "Pretty Woman" that the original publishing company sued over. It was top music industry news at the time. The case went to the Supreme Court eventually and redefined "Fair Use" laws as people know them today.
Van Halen dressed up some Kinks music as well and got boo'ed for it.
As you said, music is subjective.
Keeping with Roy Orbison, going on the RIAA info site you will find that forty five artists have legally COVERED his song "You Got It" and none of them are meant to be rip offs or remakes, but rather done in honor of one of the many artists' late and most respected heroes.
