"extensive appreciation" is correct and usable in written English.
You can use it to refer to feeling or expressing a high degree of appreciation for something. For example, "The team received extensive appreciation for their hard work and dedication."
The University of Chicago has a more extensive obituary appreciation on its main site.
Saintsbury deliberately formulated no philosophy of criticism; however, certain principles underlie his writing: extensive reading, intuitive appreciation, comparative assessment, and ranking.
Françoise and her husband have extensive knowledge and appreciation of comics.
In looking (and asking) around online, I realize now that there is extensive evidence of ongoing appreciation for the cassette — or at least the idea of the cassette.
Anderson's lectures on education are of interest because they include the most extensive account of his appreciation for the classicism of Matthew Arnold, but more particularly of his attitude towards the philosophy of John Dewey.
Kevin R. Quinn has written an appreciation and an extensive history at www.fortpeckdam.com, a site by Rafe Sigmundstad.
That menu, however, deserves appreciation; it is extensive and feastlike in itself, beginning with the three categories of appetizers — hot, cold and salad.
In addition to displaying an extensive knowledge of and aesthetic appreciation for flowers, the Ekoi create mural paintings on sanctuaries, make pottery, and carve figures in solid basaltic blocks.
A Rally for Afghanistan program also needs to spread awareness of these efforts to the broader American public, to raise appreciation of the extensive efforts in and the development potential of New Afghanistan.
