Well reviewing these as if they were going to appear in the Monstrous Manual
I would say It definitely a vast improvement over what's in there for
dragons already. The art has a lot more life in it, with a lot more polish
on top. The dragons themselves seem inspired by the cat-like dragon in
'Dragon heart' and the dinosaurs of 'Jurassic park' which aren't to my
particular tastes (dont like the overly chunky legs) and the muscles are
overly super-defined as If the artist has a ready supply of muscle mags and
reads too many bad Image comic books, but those points don't detract too
much. The best pose and work is definitely the red dragon, looking very
fierce and cool.
What I would like to see is WoTC get all the fantastic A-grade artists from
the 'Magic-the gathering' card game to work on the Monstrous Manual. There
was some exceptoinally good work done for that card game, truly exquisite
pieces. Choose epic and heroic poses, with touches of realism (realistic
elements or inspriration from nature works well), and beware of goofy fads
(or artists that can't adapt there style to the subject matter). Perhaps use
a few unconventional artists. Like in magic there was a few cards painted in
a blurry watercolour, all mood and feeling without the detail of the other
cards, but still beautiful.
In the end the art is just a support for our imaginations, but these are my
$0.02 anyway.