I'm glad that Mariano was elected - not that there was any doubt about that. The fact that he was elected unanimously is only meaningful in the sense that a barrier has been broken. Others, who should have been unanimous choices, weren't. Perhaps now, when someone else who is a true all-time great comes along, he'll be elected unanimously too.
Fwiw, I don't think that either Mussina or Schilling should be in the HoF - at least if I had a vote, I wouldn't vote for either. I do think that some of the baggage that Schilling carries affected the voting for him. I don't believe any of that should enter into the voting, but it probably does.