RebE, to be precise he is quoted as saying:
” you can declassify just by saying ‘it’s declassified’ – even by just thinking about it.””.
Possibly first part is what he means, and the second part is a guzma.
As to the need for procedure, this is l’havdil medauraita/medrabanon issue: it may be a minor aveira to not follow instructions, but he can say that he came up with a different classification approach. This should, and probably will, go to the Supreme Court that is the right avenue to deal with Presidential powers, not local judges over the whole country attacking Trump like a pack of wolves.