[akhtene]

IMHO the Valar showed that they weren't mad any more when they sent the Istari to assist the people of M-E against Sauron. Otherwise why should they have bothered?

The crowning of Aragorn by Gandalf, I think was just the final touch to Gandalf's labours, leaving the M-E in the hands of the strong and valiant King of Men. Gandalf had taught Aragorn, advised on him, led him part of the way to Gondor. By asking Gandalf to crown him (thus breaking the tradition of Gondor) Aragorn showed respect and gratitude to Gandalf. It won't be just, of course to say that it was Gandalf who made Aragorn King, but his role was the greatest.